[Q&A] MultiSystem for Android - Verizon Samsung Galaxy S 4

MultiSystem is a powerful tool for locked- and unlocked-bootloader Android devices with many features that at least includes the following:
Keeps stock system partition safe/rooted
Permenant root survival with proper use
MultiROM support via virtual ROMs
Unlimited number of virtual ROMs
Booting options to choose stock, primary, or secondary virtual ROM
Any of the virtual ROMs can work as a recovery replacement
Flashing multiple ROMs at the same time without a reboot
Ability to create/install ROMs on Linux to microSD card
Great performance & battery life on virtual ROMs
Recovery solution to install ROMs or Mods
Easy upgrade to newer versions of Android
Ability to safely apply OTA updates to virtual system
Permissive SELinux and other kernel tweaks
Safe flashing that doesn't trip KNOX flag on Samsung devices
Wrapper script runs via ADB or a Terminal Emulator on device
APK to manage all MultiSystem functions with a nice UI and extra options
Management for the best performance & user experience
Support for all Android devices with microSD card
Portability to almost all devices
Compatibility with all Android versions
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Q&A​
What is the concept behind MultiSystem?
It runs virtual Android ROMs on microSD, like booting multiple systems on a PC from different partitions/disks. So, your stock system partition is kept safe/rooted. It won't affect performance or anything (might even be better on the virtual system if you've high quality microSD & the device supports its speed). Also, you can freely modify any of the virtual systems & in the worst case, reboot the safe stock system or another working virtual system to recover. So, no root loss or potential damage to the original device partitions.
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Is it a recovery or an APK tool?
It's a shell script that hijacks system at early boot & force Android to boot from the stock system partition or a virtual system IMG & an APK that manages all booting options, virtual ROMs, and works as a recovery replacement + extra features...
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Does it work as a recovery replacement?
It IS a POWERFUL recovery replacement. You can do whatever you do in recovery with the APK. HOW? recovery does its magic b/c it doesn't depend on the system & has its own kernel/ramdisk. In MultiSystem, you can boot a virtual ROM from extSD that sure doesn't depend on stock system partition or any of the other virtual ROMs (it does depend on the kernel, which you can't flash on locked devcies anyway). Hence, install, backup, restore, ... & all recovery functions are all possible +++ more features since you're running a full ROM not just a recovery ramdisk like Safestrap.
Bottom Line: I think it's the best & most convenient recovery replacement ever for locked devices & it can also attract unlocked devices for the powerful features, MultiROM, and recovery from within ROM.
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Can I use FlashFire along with MultiSystem?
Yes. MultiSystem is compatible with FlashFire & fully supports it on stock & virtual ROMs. So, you can use both/any of them for flashing to either a stock or virtual ROM. However, it's recommended to use MultiSystem when flashing to the stock system partition (shouldn't be needed anyway since you can always be safe & flash to your old/new virtual ROMs).
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Does MultiSystem require FlashFire?
No, MultiSystem doesn't require FlashFire. They're fully combatible though.
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Would the virtual ROM we install be exactly the one in the stock slot?
In MultiSystem APK, you can create a virtual ROM from stock system, a copy from other virtual ROM, a new IMG, a dev-provided ROM, a flashable .ZIP, ... etc. Literally, your virtual ROMs can be any stock or custom ROM that's compatible with your firmware/kernel.
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How can it run virtual ROMs from external microSD card?
External MicroSD will be formated into 2 partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
It'll hijack the system & boot a virtual system from the 2nd partition. The 1st partition will be automatically detected as your extSD.
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Can I run unrooted virtual ROM for work apps or any other reason?
Yes. You can add unrooted virtual ROM & reboot to it via MultiSystem APK.
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How do you boot back into a different ROM?
MultiSystem APK manages all functions including ROM activation & reboot to current system, another stock/virtual system, download mode, recovery, ... etc.
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Will it be OK to still store media like movies/photos/music to extSD?
100% OK; That's my setup a few months ago. 2 virtual ROMs in the SECOND extSD partition in EXT4 format while all personal data are stored on the FIRST extSD partition in exFAT or FAT32 format... TWO COMPLETELY DIFFERET PARTITIONS.
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How much space are we going to have for virtual ROMs?
The size of the 2nd partition is optional (> 4GB) for your ROMs, but here is an estimated sizes:
1 Virtual ROM Uncompressed = ~2.7 GB ---> ready for running
1 Virtual ROM Compressed = ~1.5 GB ---> for full ROM backups
I'd say better allocate 4 GB for each ROM you plan to run. If you just need one virtual ROM to keep stock system safe, 4 GB 2nd extSD partition is enough; The remaining space is allocated for the 1st extSD partition as your external storage.
For me, I run Linux too from extSD via MultiSystem. So, I've 64 GB extSD card with two partitions 32 GB each.
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Can I clear up space on an existing SD card and partition it while full or will the entire card need to be wiped and partitioned from scratch?
You need to backup all your files; it'll be wiped & repartitioned.
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How can I swap microSD cards & be able to run virtual ROMs?
You can swap microSD cards as you wish provided that the device is powered off; don't remove the microSD card when running a virtual ROM. If the new microSD card doesn't include a 2nd parition of available virtual ROMs, the device will boot directly to the stock system.
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Is there a specific sd card you recommended for this?
I personally have two microSD cards:
SanDisk Extreme Plus 64GB (Up to 80MB/s read speed)
Samsung 64GB PRO (Up to 90MB/s read speed)
You don't have to change your microSD card for MultiSystem; any card you use on your device should work just fine. The need for more speed is relevant when the device supports that speed & if you're going to buy a new card anyway that you may use with a newer device later.
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Can I copy virtual ROMs to a new microSD card?
Yes. I'll add a feature for swapping microSD cards so that you can backup/restore virtual ROMs from/to the current extSD to/from internal storage as follows:
power off device
use MultiSystem APK to backup your virtual ROMs
insert the new properly formatted microSD,
power on device (it'll boot to stock system)
use MultiSystem APK to restore your virtual ROMs
use MultiSystem APK to activate one of your virtual ROMs
use MultiSystem APK to reboot to any of your ROMs
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What about other data/cache partitions and internal storage?
Only system img's are in the extSD. All ROMs share all other partitions. This substantially improves the performance & you won't notice any difference between your stock & virtual ROMs. The reason for performance improvement is that EXT4 loop devices are very fast in reading but not in writing. Your system partition is read-only while data (for example) is read write & cache IMGs cause problems like Safestrap issues on ROM slots. Also, you don't have to worry about switching data/settings between ROMs (they're shared), but you just need to regularly backup your important data (which is healthy anyway).
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Can your elaborate where data is stored?
The userdata partition is also shared; so, you'll have access to all your FULL storage partitions & all apps/data similarly on either stock or virtual ROMs. This also solves the Safestrap issue of having less storage on ROM slots...
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Will mSDcard incur a significant performance penalty on some devices?
there's no diffrerence between virtual & stock ROMs in terms of performance & battery life. The reason is simple: loop devices associated with the READ-ONLY system IMG mounted from EXT4 partition using a high-quality microSD card IS very fast more than enough.
The read speed is faster than the device can operate anyway + the exact same device should perform on the lowest speed when reading/writing from/to the FAT/FAT32/ExFAT extSD card (where you store your files or even move apps!!!) anyway, which is much slower than the read speed of a loop device mounted from EXT4 partition.
That's why data partition is shared for many reasons, including the poor READ/WRITE performance.
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If virtual systems are read only, how do we modify them? Do we have to boot to another multisystem rom to modify a virtual rom?
The stock system partition is mounted by default read only & so are the virtual systems. To modify a stock/virtual system, the MultiSystem APK remounts them read/write. You can modify the currently running virtual system, copy it & modify the copy, modify another stock/virtual system.
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How is a corrupted virtual rom handled? Does it see it's bad and default to stock system?
At early boot, MultiSystem checks for the microSD & active virtual ROM to boot it. There's a boot menu that gives you options to select a stock/virtual system, but it crashes on LP. I'm debugging it, but all functions won't be affected if I removed it. To fail safe, you can remove the microSD card to boot to stock system & restore/repair your virtual ROMs.
UPDATE1: MultiSystem v1.0.1 now allows you to also switch to stock system on boot to repair corrupted virtual IMGs or any other reasons. More options will be added during boot to ultimately select another virtual system if the active IMG is not booting normally (e.g., bootloop after applying a mod or flashing a bad .ZIP).
UPDATE2: Now, on boot, you can choose from two primary/secondary virtual ROM or stock ROM. Flashing multiple ROMs at the same time without a reboot is now possible.
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How to check if an IMG is corrupted using MultiSystem status?
Code:
Current System IMG: Test_Rom.img
Current System DEV: [B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
When you see "/dev/block/mmcblk0p23"; it's the original system partition; so MultiSystem failed to boot Test_Rom.img, but it should be your current system.
So, the check is simple based on "Current System Device":
/dev/block/mmcblk0p23 = Stock System Partition
/dev/block/loop0 = Virtual System IMG
Note: The block device number (mmcblk0p23) may vary per device & per variant !
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Does android do any maintenance whatsoever on stored data within /data or external sd? So if I have an app installed on 1 system and not on another system will android see it and clear the data?
No, all storage partitions are shared between ROMs. If you installed an app, it'll be availabe for all of them. Since on locked devcies we're limited to stock manufacturer-based ROMs, this makes the switch between ROMs very convinient (you don't have to worry about your changes/data/setup & storage space on the another ROM; all ROMs share everything except system). However, you should make regular backups in case a virtual ROM (probably with unsafe mods) results in bootloop due to your user data. In this case, it's safe to wipe data & selectively restore apps/data from backup(s). Another advantage of sharing all storage partitions is that your messages/emails/etc received on a virtual ROM are immediated synced (actually shared) to the other ROMs.
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Will anything like Xposed modify the virtual ROM system IMG as opposed to the stock system IMG?
When you run a Virtual System, everything incldung kernel & apps are hijacked to speak to it as the original system.
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Can we install AOSP ROMs on locked devices?
You can only install stock/manufacturer-based ROMs on locked devices while unlocked devices can use kexec or flash the required kernel to boot any AOSP/Stock ROMs. I've got a Note 4 Developer Edition & a lot of development is planned to go there (thanks to the unlocked bootloader!) More devices will get supported including unlocked TMO & international variants after adding more features untilizing the unlocked bootloader with kexec'd kernels.
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Are there limitations to the combinations of ROMs that can be loaded on the "stock" and "virtual" slots? Can you mix KK and LP?
Yes, if they can run on the same kernel. LP won't run on KK kernels & so, you'd have to upgrade the firmware anyway. As for running mixed compatible Android versions, this is possible but your'd have to backup your data before switching ROMs; if it cause no issues, enjoy smooth switch & if it doesn't, do factory reset in recovery & restore your data backup. Backups via MultiSystem are painless.
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Are applications installed once for each ROM slot that has that applicaiton installed, or can I share a game across ROMs (for instance?)
Everything is shared between ROMs, which is very good for storage & for easy switching. Just make regular backups of your sensitive data.
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How there are no performance hits while internal storage memory was much faster than any microSD technology?
Read speeds from microSD is very fast compared to write speeds & since virtual ROMs are actually a virtual read-only systems (hence, MultiSystem), they provide a high performance. Moreover, again, read speeds from EXT4 loop devices are higher compared to physical partitions. They're very bad in writing, which we don't need for the read-only "system".
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Is there a preferred "daily driver" ROM that should be installed in the stock slot?
Uses a stock ODEXED ROM on stock slot for better stability!
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Is it based off of Safestrap?
Short answer NO. I've been working on MultiSystem & Safestrap for ~7 months. Earlier versions of MultiSystem (called, JasmineREC) was based on Safestrap, but it failed to support newer versions of Android mainly due to TWRP changes in the graphics/UI libraries that cause segmentation fault & the stock kernel framebuffer issues. Then, I decided to find another solution. However, the basic idea of system hijack is powered by Safestrap (or 2nd-init recoveries in general) & all the work done by @Hashcode is GREATLY appreciated.
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How can it overwrite system files while running?
MultiSystem allows you to install safe mod's or a ROM in full or OTA-like update. It's strongly recommended to install .ZIP files NOT to the current system, b/c some files can not be overwritten while running. So, you can use backup function to copy the current system & install to the new img or any of your other virtual systems. You'll have several options to activate a virtual img & reboot directly to stock system, any virtual img you've activated, quick reboot, Download/bootloader, recovery,... etc.
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How would I benefit from it if I'm only running Stock ROM or would there be no point for me to install it?
If you run a ROM on stock system, you're vulnerable to root loss unless/untill a new rooting method for LP comes out. MultiSystem gives you the option to run safe-to-mod virtual ROMs + recovery replacement + extra features.
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Is there a way to convert a normal ROM .ZIP into MultiSystem .IMG?
Create or copy any of your IMGs, activate it & reboot to the active IMG! Then, use FlashFire to flash the ZIP file. However, the updater-script should be safe/compatible. Some devs mount the phyical partition, which will redirect everything to it!!
For example:
Code:
mount(“ext4″, “EMMC”, “/dev/block/mmcblk0p23″, “/system”);
will mount the original system partition; while
Code:
run_program("/sbin/mount", "-t", "auto", "/system");
will mount the current system (stock or virtual). This is recommended/safe.
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Would a KitKat ROM work with multisystem even though my stock is Lollipop?
Any ROM requires a compatible kernel & modem. So, running KK ROMs requires flashing KK firmware (namely, kernel & modem). This may work with MultiSystem on other devices, especially if the bootlpoader is unlocked. For example, I plan to add features for Note 4 DevED to allow different Android versions (including AOSP, manufacturer-based, & probably Linux systems) by utilizing kernel swapping or execution.
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When MultiSystem comes out will it be open sourced?
Most probably, haven't decided yet!
Anyway, here's the repository on GitHub: https://github.com/hsbadr/MultiSystem
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Video Tutorials
A quick preview of MultiSystem v1.0 tested on Lollipop for VZW Note 3. The video has been captured on a stable virtual ROM of JasmineROM v5.0.1. It's FULLY compatible with FlashFire on virtual/stock systems. More devices will get supported as well, after required testing.
Facebook: https://www.facebook.com/hsbadr/videos/vb.331488823689599/428178174020663

How to check if you are running a Stock/Virtual System?
There're many ways to check whether you're running a Stock or Virtual system. MultiSystem app should include this simple check at some point. That's important to avoint ruining the Stock system & keep it safe. To make it clear to NOOBZ & anyone who's requesting "another" proof even though I owe hime nothing. Very weird!
Anyway, BusyBox mountpoint applet can print the current block/device mounted to /system mountpoint by running the following command:
Code:
busybox mountpoint -n /system
The stock system is mounts the original system partition:
Code:
[B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
while the virtual system mounts a loop device associated with a system IMG:
Code:
[B][COLOR="Blue"]/dev/block/loop0[/COLOR][/B]
Here're two videos for both stock & virtual systems...
UPDATE:
Now, you could run the following command to print the current system (stock or virtual) and the system device (physical partition or loop device):
Code:
MultiSystem status
Note: The block device number (mmcblk0p23) may vary per device & per variant !

How to repartition microSD card for MultiSystem?
You can use any tool/program for partitioning on Android, Linux, Mac, or Windows. For example, MiniTool Partition Wizard is a good partitioning tool for Windows. So, let's use it for this task. Simply, you need to follow this PDF tutorial (thanks to @carl1961). In sum:
Step 1: delete old partitions on SD card
Step 2: create FAT32 PRIMARY partition
Step 3: create EXT4 PRIMARY partition
Then, apply changes (note that the program UI may get changed in newer versions).
Notes:
This partitioning tutorial doesn't create PRIMARY partitions (it creates logical partitions). So, you need to change "Create As" from "Logical" to "Primary" when creatig a partition.
The sizes of the two partitions are arbitrary depending on number of ROMs you plan to install on the 2nd EXT4 partition.
The 1st partition (check size) is automatically detected as your external storage
In Terminal Emulator or ADB shell, check the existence of the two partitions by running the following command (in red):
Code:
[email protected]:/ # [COLOR="Red"]ls -l /dev/block/platform/msm_sdcc.3/[/COLOR]
drwxr-xr-x root root 2015-05-02 21:08 by-num
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1 -> /dev/block/mmcblk1
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p1 -> [COLOR="Blue"]/dev/block/mmcblk1p1[/COLOR]
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p2 -> [COLOR="Blue"]/dev/block/mmcblk1p2[/COLOR]
/dev/block/mmcblk1p1 is mounted by Android as your external storage.
/dev/block/mmcblk1p2 is NOT mounted & will be your MultiSystem partition.
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How to check microSD card partitions for MultiSystem?
You need to correctly repartition microSD card into two partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
Use the directions in this post!
You should check your 2nd SD partition in EXT4 format mounted to /MultiSystem:
check that the /MultiSystem directory exists after a reboot
check that the 2nd SD partition (/dev/block/mmcblk1p2) is mounted to /MultiSystem by running the following command in Terminal Emulator or ADB shell:
Code:
mount | grep /MultiSystem
The output should be:
Code:
/dev/block/mmcblk1p2 /MultiSystem ext4 rw,seclabel,relatime,data=ordered 0 0

How to check MultiSystem Installation?
The 1st thing to do after installing MultiSystem is to check the /MultiSystem directory & its contents (it shouldn't be empty!). Then, check usage by running the following commands in Terminal Emulator or ADB shell:
Code:
su
bash
MultiSystem
If it retuns "MultiSystem not found" or permission denied, try to use open MultiSystem app to Update Configurations & try again. If this does't fix it, try the following command:
Code:
/MultiSystem/bin/MultiSystem
This should work if you've MultiSystem binaries installed in (extracted to) /MultiSystem directory. If so, you can create a symlink in /system/xbin as follows:
Code:
mount -o remount,rw /system
ln -sv /MultiSystem/bin/MultiSystem /system/xbin/MultiSystem
Then, test it by running:
Code:
MultiSystem
The last thing before using it is to check the boot options: reboot & monitor the GREEN LED indicator for 3 seconds (change in the app) , which give you the following options:
Volume UP = Primary virtual ROM
Volume DOWN = Secondary virtual ROM
HOME KEY = Stock System
Sure, you should have installed one or more virtual ROMs.
Backup & restore or creating/installing a virtual ROM are easy as copy & paste: all img's will be at
Code:
/MultiSystem/img/system
To backup a virtual/stock system, you have many options:
Use create function to create from stock system
Use copy function to copy the IMG
Copy & paste with a new name
Use FlashFire (fully supported on virtual/stock ROMs)
...
If you've IMG mounting issues, run the following commands:
Code:
mount -o remount,rw /system
busybox ln -sv /proc/self/mounts /system/etc/mtab
If this doesn't help, try mounting from Terminal Emulator or ADB shell after selecting the IMG in MultiSystem app, by running the following command:
Code:
MultiSystem mount virtual

MultiSystem Video Tutorial
Thanks To: @Tomsgt , aka RootJunky
Don't forget to subscribe & like the video to show appreciation of his great effort & time spent in making the video :highfive::good:

No AOSP roms, what's the point?
Don't mean to be a Negative Nancy here but what is the point if locked bootloaders cannot run AOSP roms on this. My locked bootloader S4 has always been able to run stock roms and those with unlocker bootloaders have always been able to enjoy the freedoms Multisystem can provide for them anyway. This doesn't seem to change the game at all.
Once again those with locked bootloaders are left out in the cold.

Related

[Kernel/OS] Firmware 2.1.04 on EXT4, Internal or SD, OC Kernel

I made this to tide myself over until $auron can finish UrukDroid 0.6. This is a combination of the stock Archos 2.1.04 firmware, Ardatdat's Overclocked Kernel, and a manual EXT4 Conversion. It is permanently rooted and includes SuperUser. My main reason for making it was to enable read/write access to the filesystem, which rooting DOES NOT do on the stock Archos firmware, as the squashfs will still be mounted read only by /etc/mountpoints. Also, EXT4 is much faster than the compressed squashfs Archos uses. Quadrant gives ~2200 with the data partition converted to EXT4 as well, ~1800 without conversion. I have already updated Busybox to a fully compiled version, 1.16, another thing Archos decided to "secure" despite the supposed Open Source status. I have NOT edited the .hosts file to block ads, as I believe the app developers deserve to make some money, you'd be amazed how little they make, but you can do it yourself without Archangel scripts now, as the filesystem will be read/write again.
I designed it on an A101it, but it should work on any Gen8 with internal flash storage. A70H users, I can't remember your block allocations, it may work fine, but I'll need someone to post the storage layout of /dev/block/ to be sure.
For the power users, here's a quick install outline: First, make a second partition on your storage/sdcard in EXT4, extract the rootfs.tar.gz to it, and flash the appropriate initramfs and zimage. Pretty easy.
For the rest of you(probably most of you):
There is only one short step in Linux, which is setting up an EXT4 partition on your Internal Storage or your SD Card. You must make it as a second partition, not 1st, 3rd, or anything else. This means you can still use it as a storage device as well as running Android. I find it incredibly simple, and can be done in less than 3 minutes, but I will be relying on you guys to tell me what you don't understand, and I will update the instructions as needed.
This can be run off the SD Card or the Internal Storage, both versions are included in the download. It will use the existing data partition if you already have the SDE installed and 2.1.04 firmware. Otherwise, you will need to flash the SDE, which erases your data, so please use Titanium Backup first if necessary.
Step 1:
Download my files:http://www.multiupload.com/HR6SRRR8P8
And install the SDE from Archos: http://www.archos.com/support/download/firm_dev/firmware_archos_android_gen8.aos.
Step 2: Boot into stock Android and connect to a Linux PC. If you do not have Linux, download Tuxboot and use it to create a GParted Live Disk:http://gparted.sourceforge.net/liveusb.php
Step 3:
Mount your Internal Storage/SD Card from the Archos. It should now show up in GParted on the Linux PC, make sure you have the correct device selected, it should be called Archos A101T(make note of the location, e.g. /dev/sdb). Resize your existing partition with GParted, leaving about 300MB at the end of the Internal Storage/SD Card. Make a new partition in the empty space, and select ext4 as filesystem. Apply Changes. Now open a terminal, elevate yourself to root by typing
Code:
sudo -s
and format the new partition by typing
Code:
mkfs.ext4 -O ^huge_file /dev/sdb2
Substitute "sdb" for whatever your device location was in GParted. The "2" on the end of "sdb" denotes that it is the second partition. Do NOT format "sdb1" or any other "sd"s. Mount the new partition by opening Nautilus or any other file manager and double clicking on the "300MB Filesystem" entry on the left. Untar the rootfs.tar.gz from my files with the Archive Manager, it works just like winzip or winrar, into the root of the new partition. Eject the device from Linux, then reboot into the Developer Menu by holding vol- or vol+ while booting.
Step 4:
Flash the initramfs.cpio.gz and the zimage from my files. Use the files from the "internal" folder if you are running from Internal Storage, or the files from "sdcard" if you are running from the SD Card.
Step 5:
Use the Dev Menu to boot into Developer Edition. Let me know about any bugs. After I removed the Android Boot option from the Dev Menu, I had a few strange loops of the Archos animation while booting, but it did boot, and function, just fine.
Thanks go to Ardatdat for the kernel, Archos for the crappy "securing" of the squashfs, and $auron for motivating me to get back into development.
Hi msticninja ,
I did it It seems so smooth. I used my internal storage. But linux steps were not so simple for me I used a Fedora 14 VMWare image.
I'm at work so I can't play with it but it seems stable and it can awake.
Quadrant (I know it's not accurate) score is about 1900 (internal and ext4).
I think that you should add some descriptions about linux steps (for noobs like me).
Thanks...
PS: Did I move my DATA partition to EXT4? (I did all steps you wrote). If no how can I do?
Nice work! I'll be trying to add more instructions for the Linux section for the next couple of days.
Your data partition is still EXT3, I haven't found a very easy way to convert it yet. Basically, I made another partition on the Internal Storage, copied the data partition there, and flashed a new initramfs to boot off the new data partition. Then you fdisk and format the original partition from a terminal in the Archos or ADB, copy everything back, and flash ANOTHER initramfs to use the original, now EXT4, partition.
So far, I don't think the performance gain for the data partition is worth all that work.
It works and installs well but your guide how to install it is not complete. For example, I had to manually maintain write permissions of the partition and sudo is needed by the mkfs.ext4 -O ^huge_file /dev/sdb2
Hondaracer said:
It works and installs well but your guide how to install it is not complete. For example, I had to manually maintain write permissions of the partition and sudo is needed by the mkfs.ext4 -O ^huge_file /dev/sdb2
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Sorry, i automatically elevate permissions when I do stuff like this. I've added sudo to the instructions. As far as manually maintaining the partition permission, what did you have to do there?
msticninja said:
Sorry, i automatically elevate permissions when I do stuff like this. I've added sudo to the instructions. As far as manually maintaining the partition permission, what did you have to do there?
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I had to type this: sudo chown -R username:usergroup /media By the way thanks for the work you've done
Hondaracer said:
I had to type this: sudo chown -R username:usergroup /media By the way thanks for the work you've done
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If that was before using mkfs.ext4, then that is strange. After mkfs though, the owner should be root. I should point out that the rootfs.tar.gz should be extracted as root, which means you have to open the archive manager from a terminal. I need to find an easy process that will work on all distros, as I don't know how many have nautilus installed.
Thanks for your replies, this is much needed feedback.
msticninja said:
If that was before using mkfs.ext4, then that is strange. After mkfs though, the owner should be root. I should point out that the rootfs.tar.gz should be extracted as root, which means you have to open the archive manager from a terminal. I need to find an easy process that will work on all distros, as I don't know how many have nautilus installed.
Thanks for your replies, this is much needed feedback.
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Click to collapse
I had to do this to be able to write the rootfs to dev/sdb2. But I must say I did a reboot before I copied the files cause Ubuntu started to act very weird. And for the beginner I'd might be good to mention that you have to unmount in GParted.
I've tried it and feels slower than Uruk 0.6RC2 on Scandisk SDHC 8GB Class 4 (without OC).
Thank you for your great work!
chisco said:
I've tried it and feels slower than Uruk 0.6RC2 on Scandisk SDHC 8GB Class 4 (without OC).
Thank you for your great work!
Click to expand...
Click to collapse
I'm not surprised. This is the stock firmware with none of Uruk's enhancements, other than ext4 and a new kernel. As i said, this is to tide people over until the official Uruk thread gets 0.6. You're already on the beta 0.6, so there's not much need for my firmware.
I just wrote an automatic install script. All you have to do is copy a file to your internal storage or sd card, and flash the initramfs/zimage in the Dev Menu. This one will replace the current Archos partition so you won't lose any space on your storage device. Should be uploaded tonight.
I tried this method with last OC Kernel (11 FEB): very good... With this method, we use same data as for stock ROM, so no need to reinstall all apps...
Thanks.

Using 2 Ext4 partitions on SD instead of one Ext+fat32

My sdcard(class 4 8gb sandisk) is causing problems with fat32 fs...i use debian all the time and wud like to have a much advanced fs like ext4 for saving my music,videos,pictures etc instead of fat32...how can i achieve taht...Does android use a fstab or something for mounting on boot ???
I'm quite sure android uses fstab for mounting, you just need to set the proper mounting option on your FS to force it to check fstab options. I have one question(since I don't use a linux machine), can you access your ext(2nd) partition(if you have one) when you connect your phone to the PC using debian?
Yep,Android uses fstab to mount all.
anybody interested in setting it up i dont have the requisite knowhow
I have not toyed with fstab myself... but I did find this page which seems to have want your looking for.
http://androidandme.com/2009/08/news/how-to-manually-partition-your-sd-card-for-android-apps2sd/
It isn't exactly what your explaining, BUT seems to go through the commands needed for what you are wanting to try.
Just remember to back up! Good luck!
Sent from my LG-P500 using XDA App
Instructions:
-Suggested at least fat32 partition to be 1gig and the rest to your ext partition. Also, try to use root explorer for everything else. Must have init.d support.
1. On your SD card, make a folder to serve as a door/portal to access your ext partition files.(When testing this, I just used the default "/sdcard/media" folder)
2. Make a blank text file and name it as "11usext"
3. Using root explorer, edit the file and add this line inside it:
Code:
#!/system/bin/sh
busybox mount -t auto /dev/block/mmcblk0p2 /mnt/sdcard/media
change media to the folder that you just made on step 1. Exit and save.
4. Using root explorer move this file to /system/etc/init.d
5. Again using root explorer, change the permission to "rwxrwxrwx"
6. Reboot and play. This would allow you to access your ext partition through the /media or the folder that you have created.
If this does not work, then you should give more details on what setup you are running.
ungaze said:
Instructions:
-Suggested at least fat32 partition to be 1gig and the rest to your ext partition. Also, try to use root explorer for everything else. Must have init.d support.
1. On your SD card, make a folder to serve as a door/portal to access your ext partition files.(When testing this, I just used the default "/sdcard/media" folder)
2. Make a blank text file and name it as "11usext"
3. Using root explorer, edit the file and add this line inside it:
Code:
#!/system/bin/sh
busybox mount -t auto /dev/block/mmcblk0p2 /mnt/sdcard/media
change media to the folder that you just made on step 1. Exit and save.
4. Using root explorer move this file to /system/etc/init.d
5. Again using root explorer, change the permission to "rwxrwxrwx"
6. Reboot and play. This would allow you to access your ext partition through the /media or the folder that you have created.
If this does not work, then you should give more details on what setup you are running.
Click to expand...
Click to collapse
That's a quite dirty implementation. All he want's is an ext4 partition mounted as /sdcard. I want to do the same, but right now I'm messing with the internal fs. I'll look into it.
That's a quite dirty implementation.
Click to expand...
Click to collapse
Dirty it might be(I even tried a dirtier one), but that's all he's got at the moment. If you have a better solution(even just a rough plan), please do share. Maybe we can exchange knowledge on stuff like these.
Using 2 Ext4 partitions on SD instead of one Ext+fat32
Click to expand...
Click to collapse
Would mean that no Fat32 partition exist, and I've never heard of anything like that.
I have one question(since I don't use a linux machine), can you access your ext(2nd) partition(if you have one) when you connect your phone to the PC using debian?
Click to expand...
Click to collapse
And since no one answered this, I have no idea how you could transfer files to your phone without using card readers.
ungaze said:
Dirty it might be(I even tried a dirtier one), but that's all he's got at the moment. If you have a better solution(even just a rough plan), please do share. Maybe we can exchange knowledge on stuff like these.
Click to expand...
Click to collapse
Probably it involves messing with the init.rc (and I think that involves messing with boot and recovery images, but, I'm not sure) or init.d scripts or fstab. Anyway, I'm not sure, but it should be possible.
ungaze said:
Would mean that no Fat32 partition exist, and I've never heard of anything like that.
Click to expand...
Click to collapse
Yes. The /sdcard partition would exist, just not fat32 formatted.
ungaze said:
And since no one answered this, I have no idea how you could transfer files to your phone without using card readers.
Click to expand...
Click to collapse
Linux systems can read and write to ext4 partitions without problems. In fact, it's a linux filesystem. I had problems once when I had a sd_ext partition (for Apps2SD), because both partitions would get mounted when using mass storage mode, while Android only unmounts the /sdcard (fat32) partition, leading to file corruption (because of the same partition being mounted on both systems at once).
We could create the partitions using gparted or cfdisk on a pc. I'm not sure, but maybe simply mounting it with different params (like the filesystem type and other options) at /sdcard would do the trick. Everything else that follows would be easy.
I've been doing some testing and research.
On recovery side:
I've done a little modification in Mik's ClockWork recovery to make it accept ext4 and vfat as valid file systems for the first partition on sdcard. It involves just a little change on /etc/recovery.fstab file, but then you need to rebuild the recovery image.
This is working fine.
On the OS side:
It's not an easy mod. It involves patching the vold (volume manager) and recompiling. There are some proposed patches to Cyanogenmod, but I don't know if it's been accepted and if it made it to Miks CM7 port.
I'll do some tests and post results.
ilarrain said:
I've been doing some testing and research.
On recovery side:
I've done a little modification in Mik's ClockWork recovery to make it accept ext4 and vfat as valid file systems for the first partition on sdcard. It involves just a little change on /etc/recovery.fstab file, but then you need to rebuild the recovery image.
This is working fine.
On the OS side:
It's not an easy mod. It involves patching the vold (volume manager) and recompiling. There are some proposed patches to Cyanogenmod, but I don't know if it's been accepted and if it made it to Miks CM7 port.
I'll do some tests and post results.
Click to expand...
Click to collapse
This got my interest
Mik's CM7 (beta 6.2) recognizes and mounts the ext4 partition just fine.
BUT:
As vfat is a non posix fs, there wasn't any need for the OS to manage permissions, so it's a mess.
Applications on the SD card (I'm not using Apps2SD or Data2SD) don't load, internal applications can't be moved to SD, and many apps can't store data on the SD, even I've set read+write permissions on all files and directories (chmod -R 777 /sdcard/). I have no idea why. I'm stuck.

Solved -- Running safestrap on sdcard -- looking for input

So I got tired of my weird configuration of running the apps in a mounts2sd with a second ext4 partition on my sdcard and technically nothing should prevent us from running safestrap on the sdcard. So I looked around and it took me a while but I found Hashcode's source code and spent some time studying all the voodoo he does, and most of it is fairly straight forward. Small breakdown:
* Extend TWRP with ifdef statement to add new buttons
* sh scripts get called to perform the functionality for those button
* Swap out some links in /dev/block when you switch between slots and stock
* The entire boot partition including scripts, TWRP, etc are stored in boot image
* The boot image is stored in the stock system under /etc/safestrap
Like I said before, most of the functionality is done in borne shell scripts, but there is some hardcoding in TWRP like creating the .img file to /ss. I really don't want to try to recompile TWRP at this time. As such, I want to limit my changes to the borne shell and configuration INI files only. The simplest answer is to remap /ss from internal storage to the sdcard storage. Another option is to have "system" and "cache" in the internal storage and moving "data" to the sdcard. The difficulty here is since TWRP is hardcoded to create the .img file under /ss, I need to move it during the format stage which happens in the script. The danger with the first option I don't know if the phone will boot if the sdcard is removed. safestrap looks for that directory to figure out the mappings in /dev/block. I think if the directory is missing then it will attempt to create it. After that, things might go bad.
Anyway, what are your thoughts?
i wish and hope your still working on this..my phone is so low in internal storage..i cant even use a rom slot other than stock,,ive been useing stock slot ,flashing custom rom in stock slot....anyways hope you continue to figure this out..i know lots of people would appreciate it..thanks
So I've tried multiple ways and have had to step away, think about it some more, and come back to it. Essentially I was not able to get system to boot off of the sdcard. However, the good news is today I was able to have system and cache on internal storage and data on sdcard. So here are the keys to the kingdom that I have found....
The CM11 (and I assume other) ROMs there is a /system/etc/kexec/ramdisk.img file. This file is extracted (gunzip < ramdisk.img | cpio -iu) into the root directory "/" (rootfs). There is a shell script "/sbin/fixboot.sh" that gets executed by /init at the start of the android (on fs). That script essentially mounts /ss to /emstorage and does all the loop storage links to the system.img, cache.img, and data.img files. I was able to mount another /ss2 to my sdcard and point the userdata to /ss2/safestrap/rom-slot?/userdata.img. The limitation is that vfat limits all files to 4 GB max, so the userdata.img cannot be more than 4 GB of storage.
So an option is I can create an updated ramdisk.img file. You would just drop this into your /system/etc/kexec directory on the slot-rom you want to use it. The only file changed in ramdisk.img is /sbin/fixboot.sh. ramdisk.img is part of the CM11 distribution so you would need to replace it each time you perform an update on that rom slot. Other than that, safestrap would by default create userdata.img to be in internal storage.
The next part I'm going to look at is to create a f2fs partition on my sdcard and have my userdata use that f2fs partition. I figure I should good considerable more I/O as f2fs is suppose to be a good amount faster than ext3/4 and we wouldn't be going through a loop device from ext3 to vfat for all I/O. In addition, my data partition would no longer be limited to 4GB due to the file limitation size of vfat.
Thoughts...
So Spyder doesn't have f2fs on it so I've been running ext4. The kernel would need to be setup to be compiled with it. I have a second 6Gb partition formatted with ext 4 with writeback journaling but per my timing tests I don't think it has made a difference. Now I have more than enough space left in both the data and internal partitions. I don't know if it is just a placebo effect but my apps do seem to start slightly faster.
There doesn't seem much interest in this but it was a fun exercise for me. This will be good enough for me as I'll probably upgrade my phone sometime in the future.
Sent from my XT912 using XDA Free mobile app

[Q&A] MultiSystem for Android

MultiSystem is a powerful tool for locked- and unlocked-bootloader Android devices with many features that at least includes the following:
Keeps stock system partition safe/rooted
Permenant root survival with proper use
MultiROM support via virtual ROMs
Unlimited number of virtual ROMs
Booting options to choose stock, primary, or secondary virtual ROM
Any of the virtual ROMs can work as a recovery replacement
Flashing multiple ROMs at the same time without a reboot
Ability to create/install ROMs on Linux to microSD card
Great performance & battery life on virtual ROMs
Recovery solution to install ROMs or Mods
Easy upgrade to newer versions of Android
Ability to safely apply OTA updates to virtual system
Permissive SELinux and other kernel tweaks
Safe flashing that doesn't trip KNOX flag on Samsung devices
Wrapper script runs via ADB or a Terminal Emulator on device
APK to manage all MultiSystem functions with a nice UI and extra options
Management for the best performance & user experience
Support for all Android devices with microSD card
Portability to almost all devices
Compatibility with all Android versions
Click to expand...
Click to collapse
Q&A​
What is the concept behind MultiSystem?
It runs virtual Android ROMs on microSD, like booting multiple systems on a PC from different partitions/disks. So, your stock system partition is kept safe/rooted. It won't affect performance or anything (might even be better on the virtual system if you've high quality microSD & the device supports its speed). Also, you can freely modify any of the virtual systems & in the worst case, reboot the safe stock system or another working virtual system to recover. So, no root loss or potential damage to the original device partitions.
Click to expand...
Click to collapse
Is it a recovery or an APK tool?
It's a shell script that hijacks system at early boot & force Android to boot from the stock system partition or a virtual system IMG & an APK that manages all booting options, virtual ROMs, and works as a recovery replacement + extra features...
Click to expand...
Click to collapse
Does it work as a recovery replacement?
It IS a POWERFUL recovery replacement. You can do whatever you do in recovery with the APK. HOW? recovery does its magic b/c it doesn't depend on the system & has its own kernel/ramdisk. In MultiSystem, you can boot a virtual ROM from extSD that sure doesn't depend on stock system partition or any of the other virtual ROMs (it does depend on the kernel, which you can't flash on locked devcies anyway). Hence, install, backup, restore, ... & all recovery functions are all possible +++ more features since you're running a full ROM not just a recovery ramdisk like Safestrap.
Bottom Line: I think it's the best & most convenient recovery replacement ever for locked devices & it can also attract unlocked devices for the powerful features, MultiROM, and recovery from within ROM.
Click to expand...
Click to collapse
Can I use FlashFire along with MultiSystem?
Yes. MultiSystem is compatible with FlashFire & fully supports it on stock & virtual ROMs. So, you can use both/any of them for flashing to either a stock or virtual ROM. However, it's recommended to use MultiSystem when flashing to the stock system partition (shouldn't be needed anyway since you can always be safe & flash to your old/new virtual ROMs).
Click to expand...
Click to collapse
Does MultiSystem require FlashFire?
No, MultiSystem doesn't require FlashFire. They're fully combatible though.
Click to expand...
Click to collapse
Would the virtual ROM we install be exactly the one in the stock slot?
In MultiSystem APK, you can create a virtual ROM from stock system, a copy from other virtual ROM, a new IMG, a dev-provided ROM, a flashable .ZIP, ... etc. Literally, your virtual ROMs can be any stock or custom ROM that's compatible with your firmware/kernel.
Click to expand...
Click to collapse
How can it run virtual ROMs from external microSD card?
External MicroSD will be formated into 2 partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
It'll hijack the system & boot a virtual system from the 2nd partition. The 1st partition will be automatically detected as your extSD.
Click to expand...
Click to collapse
Can I run unrooted virtual ROM for work apps or any other reason?
Yes. You can add unrooted virtual ROM & reboot to it via MultiSystem APK.
Click to expand...
Click to collapse
How do you boot back into a different ROM?
MultiSystem APK manages all functions including ROM activation & reboot to current system, another stock/virtual system, download mode, recovery, ... etc.
Click to expand...
Click to collapse
Will it be OK to still store media like movies/photos/music to extSD?
100% OK; That's my setup a few months ago. 2 virtual ROMs in the SECOND extSD partition in EXT4 format while all personal data are stored on the FIRST extSD partition in exFAT or FAT32 format... TWO COMPLETELY DIFFERET PARTITIONS.
Click to expand...
Click to collapse
How much space are we going to have for virtual ROMs?
The size of the 2nd partition is optional (> 4GB) for your ROMs, but here is an estimated sizes:
1 Virtual ROM Uncompressed = ~2.7 GB ---> ready for running
1 Virtual ROM Compressed = ~1.5 GB ---> for full ROM backups
I'd say better allocate 4 GB for each ROM you plan to run. If you just need one virtual ROM to keep stock system safe, 4 GB 2nd extSD partition is enough; The remaining space is allocated for the 1st extSD partition as your external storage.
For me, I run Linux too from extSD via MultiSystem. So, I've 64 GB extSD card with two partitions 32 GB each.
Click to expand...
Click to collapse
Can I clear up space on an existing SD card and partition it while full or will the entire card need to be wiped and partitioned from scratch?
You need to backup all your files; it'll be wiped & repartitioned.
Click to expand...
Click to collapse
How can I swap microSD cards & be able to run virtual ROMs?
You can swap microSD cards as you wish provided that the device is powered off; don't remove the microSD card when running a virtual ROM. If the new microSD card doesn't include a 2nd parition of available virtual ROMs, the device will boot directly to the stock system.
Click to expand...
Click to collapse
Is there a specific sd card you recommended for this?
I personally have two microSD cards:
SanDisk Extreme Plus 64GB (Up to 80MB/s read speed)
Samsung 64GB PRO (Up to 90MB/s read speed)
You don't have to change your microSD card for MultiSystem; any card you use on your device should work just fine. The need for more speed is relevant when the device supports that speed & if you're going to buy a new card anyway that you may use with a newer device later.
Click to expand...
Click to collapse
Can I copy virtual ROMs to a new microSD card?
Yes. I'll add a feature for swapping microSD cards so that you can backup/restore virtual ROMs from/to the current extSD to/from internal storage as follows:
power off device
use MultiSystem APK to backup your virtual ROMs
insert the new properly formatted microSD,
power on device (it'll boot to stock system)
use MultiSystem APK to restore your virtual ROMs
use MultiSystem APK to activate one of your virtual ROMs
use MultiSystem APK to reboot to any of your ROMs
Click to expand...
Click to collapse
What about other data/cache partitions and internal storage?
Only system img's are in the extSD. All ROMs share all other partitions. This substantially improves the performance & you won't notice any difference between your stock & virtual ROMs. The reason for performance improvement is that EXT4 loop devices are very fast in reading but not in writing. Your system partition is read-only while data (for example) is read write & cache IMGs cause problems like Safestrap issues on ROM slots. Also, you don't have to worry about switching data/settings between ROMs (they're shared), but you just need to regularly backup your important data (which is healthy anyway).
Click to expand...
Click to collapse
Can your elaborate where data is stored?
The userdata partition is also shared; so, you'll have access to all your FULL storage partitions & all apps/data similarly on either stock or virtual ROMs. This also solves the Safestrap issue of having less storage on ROM slots...
Click to expand...
Click to collapse
Will mSDcard incur a significant performance penalty on some devices?
there's no diffrerence between virtual & stock ROMs in terms of performance & battery life. The reason is simple: loop devices associated with the READ-ONLY system IMG mounted from EXT4 partition using a high-quality microSD card IS very fast more than enough.
The read speed is faster than the device can operate anyway + the exact same device should perform on the lowest speed when reading/writing from/to the FAT/FAT32/ExFAT extSD card (where you store your files or even move apps!!!) anyway, which is much slower than the read speed of a loop device mounted from EXT4 partition.
That's why data partition is shared for many reasons, including the poor READ/WRITE performance.
Click to expand...
Click to collapse
If virtual systems are read only, how do we modify them? Do we have to boot to another multisystem rom to modify a virtual rom?
The stock system partition is mounted by default read only & so are the virtual systems. To modify a stock/virtual system, the MultiSystem APK remounts them read/write. You can modify the currently running virtual system, copy it & modify the copy, modify another stock/virtual system.
Click to expand...
Click to collapse
How is a corrupted virtual rom handled? Does it see it's bad and default to stock system?
At early boot, MultiSystem checks for the microSD & active virtual ROM to boot it. There's a boot menu that gives you options to select a stock/virtual system, but it crashes on LP. I'm debugging it, but all functions won't be affected if I removed it. To fail safe, you can remove the microSD card to boot to stock system & restore/repair your virtual ROMs.
UPDATE1: MultiSystem v1.0.1 now allows you to also switch to stock system on boot to repair corrupted virtual IMGs or any other reasons. More options will be added during boot to ultimately select another virtual system if the active IMG is not booting normally (e.g., bootloop after applying a mod or flashing a bad .ZIP).
UPDATE2: Now, on boot, you can choose from two primary/secondary virtual ROM or stock ROM. Flashing multiple ROMs at the same time without a reboot is now possible.
Click to expand...
Click to collapse
How to check if an IMG is corrupted using MultiSystem status?
Code:
Current System IMG: Test_Rom.img
Current System DEV: [B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
When you see "/dev/block/mmcblk0p23"; it's the original system partition; so MultiSystem failed to boot Test_Rom.img, but it should be your current system.
So, the check is simple based on "Current System Device":
/dev/block/mmcblk0p23 = Stock System Partition
/dev/block/loop0 = Virtual System IMG
Note: The block device number (mmcblk0p23) may vary per device & per variant !
Click to expand...
Click to collapse
Does android do any maintenance whatsoever on stored data within /data or external sd? So if I have an app installed on 1 system and not on another system will android see it and clear the data?
No, all storage partitions are shared between ROMs. If you installed an app, it'll be availabe for all of them. Since on locked devcies we're limited to stock manufacturer-based ROMs, this makes the switch between ROMs very convinient (you don't have to worry about your changes/data/setup & storage space on the another ROM; all ROMs share everything except system). However, you should make regular backups in case a virtual ROM (probably with unsafe mods) results in bootloop due to your user data. In this case, it's safe to wipe data & selectively restore apps/data from backup(s). Another advantage of sharing all storage partitions is that your messages/emails/etc received on a virtual ROM are immediated synced (actually shared) to the other ROMs.
Click to expand...
Click to collapse
Will anything like Xposed modify the virtual ROM system IMG as opposed to the stock system IMG?
When you run a Virtual System, everything incldung kernel & apps are hijacked to speak to it as the original system.
Click to expand...
Click to collapse
Can we install AOSP ROMs on locked devices?
You can only install stock/manufacturer-based ROMs on locked devices while unlocked devices can use kexec or flash the required kernel to boot any AOSP/Stock ROMs. I've got a Note 4 Developer Edition & a lot of development is planned to go there (thanks to the unlocked bootloader!) More devices will get supported including unlocked TMO & international variants after adding more features untilizing the unlocked bootloader with kexec'd kernels.
Click to expand...
Click to collapse
Are there limitations to the combinations of ROMs that can be loaded on the "stock" and "virtual" slots? Can you mix KK and LP?
Yes, if they can run on the same kernel. LP won't run on KK kernels & so, you'd have to upgrade the firmware anyway. As for running mixed compatible Android versions, this is possible but your'd have to backup your data before switching ROMs; if it cause no issues, enjoy smooth switch & if it doesn't, do factory reset in recovery & restore your data backup. Backups via MultiSystem are painless.
Click to expand...
Click to collapse
Are applications installed once for each ROM slot that has that applicaiton installed, or can I share a game across ROMs (for instance?)
Everything is shared between ROMs, which is very good for storage & for easy switching. Just make regular backups of your sensitive data.
Click to expand...
Click to collapse
How there are no performance hits while internal storage memory was much faster than any microSD technology?
Read speeds from microSD is very fast compared to write speeds & since virtual ROMs are actually a virtual read-only systems (hence, MultiSystem), they provide a high performance. Moreover, again, read speeds from EXT4 loop devices are higher compared to physical partitions. They're very bad in writing, which we don't need for the read-only "system".
Click to expand...
Click to collapse
Is there a preferred "daily driver" ROM that should be installed in the stock slot?
Uses a stock ODEXED ROM on stock slot for better stability!
Click to expand...
Click to collapse
Is it based off of Safestrap?
Short answer NO. I've been working on MultiSystem & Safestrap for ~7 months. Earlier versions of MultiSystem (called, JasmineREC) was based on Safestrap, but it failed to support newer versions of Android mainly due to TWRP changes in the graphics/UI libraries that cause segmentation fault & the stock kernel framebuffer issues. Then, I decided to find another solution. However, the basic idea of system hijack is powered by Safestrap (or 2nd-init recoveries in general) & all the work done by @Hashcode is GREATLY appreciated.
Click to expand...
Click to collapse
How can it overwrite system files while running?
MultiSystem allows you to install safe mod's or a ROM in full or OTA-like update. It's strongly recommended to install .ZIP files NOT to the current system, b/c some files can not be overwritten while running. So, you can use backup function to copy the current system & install to the new img or any of your other virtual systems. You'll have several options to activate a virtual img & reboot directly to stock system, any virtual img you've activated, quick reboot, Download/bootloader, recovery,... etc.
Click to expand...
Click to collapse
How would I benefit from it if I'm only running Stock ROM or would there be no point for me to install it?
If you run a ROM on stock system, you're vulnerable to root loss unless/untill a new rooting method for LP comes out. MultiSystem gives you the option to run safe-to-mod virtual ROMs + recovery replacement + extra features.
Click to expand...
Click to collapse
Is there a way to convert a normal ROM .ZIP into MultiSystem .IMG?
Create or copy any of your IMGs, activate it & reboot to the active IMG! Then, use FlashFire to flash the ZIP file. However, the updater-script should be safe/compatible. Some devs mount the phyical partition, which will redirect everything to it!!
For example:
Code:
mount(“ext4″, “EMMC”, “/dev/block/mmcblk0p23″, “/system”);
will mount the original system partition; while
Code:
run_program("/sbin/mount", "-t", "auto", "/system");
will mount the current system (stock or virtual). This is recommended/safe.
Click to expand...
Click to collapse
Would a KitKat ROM work with multisystem even though my stock is Lollipop?
Any ROM requires a compatible kernel & modem. So, running KK ROMs requires flashing KK firmware (namely, kernel & modem). This may work with MultiSystem on other devices, especially if the bootlpoader is unlocked. For example, I plan to add features for Note 4 DevED to allow different Android versions (including AOSP, manufacturer-based, & probably Linux systems) by utilizing kernel swapping or execution.
Click to expand...
Click to collapse
When MultiSystem comes out will it be open sourced?
Most probably, haven't decided yet!
Anyway, here's the repository on GitHub: https://github.com/hsbadr/MultiSystem
Click to expand...
Click to collapse
Click to expand...
Click to collapse
Video Tutorials
A quick preview of MultiSystem v1.0 tested on Lollipop for VZW Note 3. The video has been captured on a stable virtual ROM of JasmineROM v5.0.1. It's FULLY compatible with FlashFire on virtual/stock systems. More devices will get supported as well, after required testing.
Facebook: https://www.facebook.com/hsbadr/videos/vb.331488823689599/428178174020663
How to check if you are running a Stock/Virtual System?
There're many ways to check whether you're running a Stock or Virtual system. MultiSystem app should include this simple check at some point. That's important to avoint ruining the Stock system & keep it safe. To make it clear to NOOBZ & anyone who's requesting "another" proof even though I owe hime nothing. Very weird!
Anyway, BusyBox mountpoint applet can print the current block/device mounted to /system mountpoint by running the following command:
Code:
busybox mountpoint -n /system
The stock system is mounts the original system partition:
Code:
[B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
while the virtual system mounts a loop device associated with a system IMG:
Code:
[B][COLOR="Blue"]/dev/block/loop0[/COLOR][/B]
Here're two videos for both stock & virtual systems...
UPDATE:
Now, you could run the following command to print the current system (stock or virtual) and the system device (physical partition or loop device):
Code:
MultiSystem status
Note: The block device number (mmcblk0p23) may vary per device & per variant !
How to repartition microSD card for MultiSystem?
You can use any tool/program for partitioning on Android, Linux, Mac, or Windows. For example, MiniTool Partition Wizard is a good partitioning tool for Windows. So, let's use it for this task. Simply, you need to follow this PDF tutorial (thanks to @carl1961). In sum:
Step 1: delete old partitions on SD card
Step 2: create FAT32 PRIMARY partition
Step 3: create EXT4 PRIMARY partition
Then, apply changes (note that the program UI may get changed in newer versions).
Notes:
This partitioning tutorial doesn't create PRIMARY partitions (it creates logical partitions). So, you need to change "Create As" from "Logical" to "Primary" when creatig a partition.
The sizes of the two partitions are arbitrary depending on number of ROMs you plan to install on the 2nd EXT4 partition.
The 1st partition (check size) is automatically detected as your external storage
In Terminal Emulator or ADB shell, check the existence of the two partitions by running the following command (in red):
Code:
[email protected]:/ # [COLOR="Red"]ls -l /dev/block/platform/msm_sdcc.3/[/COLOR]
drwxr-xr-x root root 2015-05-02 21:08 by-num
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1 -> /dev/block/mmcblk1
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p1 -> [COLOR="Blue"]/dev/block/mmcblk1p1[/COLOR]
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p2 -> [COLOR="Blue"]/dev/block/mmcblk1p2[/COLOR]
/dev/block/mmcblk1p1 is mounted by Android as your external storage.
/dev/block/mmcblk1p2 is NOT mounted & will be your MultiSystem partition.
Click to expand...
Click to collapse
How to check microSD card partitions for MultiSystem?
You need to correctly repartition microSD card into two partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
Use the directions in this post!
You should check your 2nd SD partition in EXT4 format mounted to /MultiSystem:
check that the /MultiSystem directory exists after a reboot
check that the 2nd SD partition (/dev/block/mmcblk1p2) is mounted to /MultiSystem by running the following command in Terminal Emulator or ADB shell:
Code:
mount | grep /MultiSystem
The output should be:
Code:
/dev/block/mmcblk1p2 /MultiSystem ext4 rw,seclabel,relatime,data=ordered 0 0
How to check MultiSystem Installation?
The 1st thing to do after installing MultiSystem is to check the /MultiSystem directory & its contents (it shouldn't be empty!). Then, check usage by running the following commands in Terminal Emulator or ADB shell:
Code:
su
bash
MultiSystem
If it retuns "MultiSystem not found" or permission denied, try to use open MultiSystem app to Update Configurations & try again. If this does't fix it, try the following command:
Code:
/MultiSystem/bin/MultiSystem
This should work if you've MultiSystem binaries installed in (extracted to) /MultiSystem directory. If so, you can create a symlink in /system/xbin as follows:
Code:
mount -o remount,rw /system
ln -sv /MultiSystem/bin/MultiSystem /system/xbin/MultiSystem
Then, test it by running:
Code:
MultiSystem
The last thing before using it is to check the boot options: reboot & monitor the GREEN LED indicator for 3 seconds (change in the app) , which give you the following options:
Volume UP = Primary virtual ROM
Volume DOWN = Secondary virtual ROM
HOME KEY = Stock System
Sure, you should have installed one or more virtual ROMs.
Backup & restore or creating/installing a virtual ROM are easy as copy & paste: all img's will be at
Code:
/MultiSystem/img/system
To backup a virtual/stock system, you have many options:
Use create function to create from stock system
Use copy function to copy the IMG
Copy & paste with a new name
Use FlashFire (fully supported on virtual/stock ROMs)
...
If you've IMG mounting issues, run the following commands:
Code:
mount -o remount,rw /system
busybox ln -sv /proc/self/mounts /system/etc/mtab
If this doesn't help, try mounting from Terminal Emulator or ADB shell after selecting the IMG in MultiSystem app, by running the following command:
Code:
MultiSystem mount virtual
MultiSystem Video Tutorial
Thanks To: @Tomsgt , aka RootJunky
Don't forget to subscribe & like the video to show appreciation of his great effort & time spent in making the video :highfive::good:
I remember we had this kind of thing working on Galaxy Y, it was working just excellent (tho SD card is slower than int.flash)
multisystem is very much like SAFESTRAP , google it

[Q&A] MultiSystem for Android

MultiSystem is a powerful tool for locked- and unlocked-bootloader Android devices with many features that at least includes the following:
Keeps stock system partition safe/rooted
Permenant root survival with proper use
MultiROM support via virtual ROMs
Unlimited number of virtual ROMs
Booting options to choose stock, primary, or secondary virtual ROM
Any of the virtual ROMs can work as a recovery replacement
Flashing multiple ROMs at the same time without a reboot
Ability to create/install ROMs on Linux to microSD card
Great performance & battery life on virtual ROMs
Recovery solution to install ROMs or Mods
Easy upgrade to newer versions of Android
Ability to safely apply OTA updates to virtual system
Permissive SELinux and other kernel tweaks
Safe flashing that doesn't trip KNOX flag on Samsung devices
Wrapper script runs via ADB or a Terminal Emulator on device
APK to manage all MultiSystem functions with a nice UI and extra options
Management for the best performance & user experience
Support for all Android devices with microSD card
Portability to almost all devices
Compatibility with all Android versions
Click to expand...
Click to collapse
Q&A​
What is the concept behind MultiSystem?
It runs virtual Android ROMs on microSD, like booting multiple systems on a PC from different partitions/disks. So, your stock system partition is kept safe/rooted. It won't affect performance or anything (might even be better on the virtual system if you've high quality microSD & the device supports its speed). Also, you can freely modify any of the virtual systems & in the worst case, reboot the safe stock system or another working virtual system to recover. So, no root loss or potential damage to the original device partitions.
Click to expand...
Click to collapse
Is it a recovery or an APK tool?
It's a shell script that hijacks system at early boot & force Android to boot from the stock system partition or a virtual system IMG & an APK that manages all booting options, virtual ROMs, and works as a recovery replacement + extra features...
Click to expand...
Click to collapse
Does it work as a recovery replacement?
It IS a POWERFUL recovery replacement. You can do whatever you do in recovery with the APK. HOW? recovery does its magic b/c it doesn't depend on the system & has its own kernel/ramdisk. In MultiSystem, you can boot a virtual ROM from extSD that sure doesn't depend on stock system partition or any of the other virtual ROMs (it does depend on the kernel, which you can't flash on locked devcies anyway). Hence, install, backup, restore, ... & all recovery functions are all possible +++ more features since you're running a full ROM not just a recovery ramdisk like Safestrap.
Bottom Line: I think it's the best & most convenient recovery replacement ever for locked devices & it can also attract unlocked devices for the powerful features, MultiROM, and recovery from within ROM.
Click to expand...
Click to collapse
Can I use FlashFire along with MultiSystem?
Yes. MultiSystem is compatible with FlashFire & fully supports it on stock & virtual ROMs. So, you can use both/any of them for flashing to either a stock or virtual ROM. However, it's recommended to use MultiSystem when flashing to the stock system partition (shouldn't be needed anyway since you can always be safe & flash to your old/new virtual ROMs).
Click to expand...
Click to collapse
Does MultiSystem require FlashFire?
No, MultiSystem doesn't require FlashFire. They're fully combatible though.
Click to expand...
Click to collapse
Would the virtual ROM we install be exactly the one in the stock slot?
In MultiSystem APK, you can create a virtual ROM from stock system, a copy from other virtual ROM, a new IMG, a dev-provided ROM, a flashable .ZIP, ... etc. Literally, your virtual ROMs can be any stock or custom ROM that's compatible with your firmware/kernel.
Click to expand...
Click to collapse
How can it run virtual ROMs from external microSD card?
External MicroSD will be formated into 2 partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
It'll hijack the system & boot a virtual system from the 2nd partition. The 1st partition will be automatically detected as your extSD.
Click to expand...
Click to collapse
Can I run unrooted virtual ROM for work apps or any other reason?
Yes. You can add unrooted virtual ROM & reboot to it via MultiSystem APK.
Click to expand...
Click to collapse
How do you boot back into a different ROM?
MultiSystem APK manages all functions including ROM activation & reboot to current system, another stock/virtual system, download mode, recovery, ... etc.
Click to expand...
Click to collapse
Will it be OK to still store media like movies/photos/music to extSD?
100% OK; That's my setup a few months ago. 2 virtual ROMs in the SECOND extSD partition in EXT4 format while all personal data are stored on the FIRST extSD partition in exFAT or FAT32 format... TWO COMPLETELY DIFFERET PARTITIONS.
Click to expand...
Click to collapse
How much space are we going to have for virtual ROMs?
The size of the 2nd partition is optional (> 4GB) for your ROMs, but here is an estimated sizes:
1 Virtual ROM Uncompressed = ~2.7 GB ---> ready for running
1 Virtual ROM Compressed = ~1.5 GB ---> for full ROM backups
I'd say better allocate 4 GB for each ROM you plan to run. If you just need one virtual ROM to keep stock system safe, 4 GB 2nd extSD partition is enough; The remaining space is allocated for the 1st extSD partition as your external storage.
For me, I run Linux too from extSD via MultiSystem. So, I've 64 GB extSD card with two partitions 32 GB each.
Click to expand...
Click to collapse
Can I clear up space on an existing SD card and partition it while full or will the entire card need to be wiped and partitioned from scratch?
You need to backup all your files; it'll be wiped & repartitioned.
Click to expand...
Click to collapse
How can I swap microSD cards & be able to run virtual ROMs?
You can swap microSD cards as you wish provided that the device is powered off; don't remove the microSD card when running a virtual ROM. If the new microSD card doesn't include a 2nd parition of available virtual ROMs, the device will boot directly to the stock system.
Click to expand...
Click to collapse
Is there a specific sd card you recommended for this?
I personally have two microSD cards:
SanDisk Extreme Plus 64GB (Up to 80MB/s read speed)
Samsung 64GB PRO (Up to 90MB/s read speed)
You don't have to change your microSD card for MultiSystem; any card you use on your device should work just fine. The need for more speed is relevant when the device supports that speed & if you're going to buy a new card anyway that you may use with a newer device later.
Click to expand...
Click to collapse
Can I copy virtual ROMs to a new microSD card?
Yes. I'll add a feature for swapping microSD cards so that you can backup/restore virtual ROMs from/to the current extSD to/from internal storage as follows:
power off device
use MultiSystem APK to backup your virtual ROMs
insert the new properly formatted microSD,
power on device (it'll boot to stock system)
use MultiSystem APK to restore your virtual ROMs
use MultiSystem APK to activate one of your virtual ROMs
use MultiSystem APK to reboot to any of your ROMs
Click to expand...
Click to collapse
What about other data/cache partitions and internal storage?
Only system img's are in the extSD. All ROMs share all other partitions. This substantially improves the performance & you won't notice any difference between your stock & virtual ROMs. The reason for performance improvement is that EXT4 loop devices are very fast in reading but not in writing. Your system partition is read-only while data (for example) is read write & cache IMGs cause problems like Safestrap issues on ROM slots. Also, you don't have to worry about switching data/settings between ROMs (they're shared), but you just need to regularly backup your important data (which is healthy anyway).
Click to expand...
Click to collapse
Can your elaborate where data is stored?
The userdata partition is also shared; so, you'll have access to all your FULL storage partitions & all apps/data similarly on either stock or virtual ROMs. This also solves the Safestrap issue of having less storage on ROM slots...
Click to expand...
Click to collapse
Will mSDcard incur a significant performance penalty on some devices?
there's no diffrerence between virtual & stock ROMs in terms of performance & battery life. The reason is simple: loop devices associated with the READ-ONLY system IMG mounted from EXT4 partition using a high-quality microSD card IS very fast more than enough.
The read speed is faster than the device can operate anyway + the exact same device should perform on the lowest speed when reading/writing from/to the FAT/FAT32/ExFAT extSD card (where you store your files or even move apps!!!) anyway, which is much slower than the read speed of a loop device mounted from EXT4 partition.
That's why data partition is shared for many reasons, including the poor READ/WRITE performance.
Click to expand...
Click to collapse
If virtual systems are read only, how do we modify them? Do we have to boot to another multisystem rom to modify a virtual rom?
The stock system partition is mounted by default read only & so are the virtual systems. To modify a stock/virtual system, the MultiSystem APK remounts them read/write. You can modify the currently running virtual system, copy it & modify the copy, modify another stock/virtual system.
Click to expand...
Click to collapse
How is a corrupted virtual rom handled? Does it see it's bad and default to stock system?
At early boot, MultiSystem checks for the microSD & active virtual ROM to boot it. There's a boot menu that gives you options to select a stock/virtual system, but it crashes on LP. I'm debugging it, but all functions won't be affected if I removed it. To fail safe, you can remove the microSD card to boot to stock system & restore/repair your virtual ROMs.
UPDATE1: MultiSystem v1.0.1 now allows you to also switch to stock system on boot to repair corrupted virtual IMGs or any other reasons. More options will be added during boot to ultimately select another virtual system if the active IMG is not booting normally (e.g., bootloop after applying a mod or flashing a bad .ZIP).
UPDATE2: Now, on boot, you can choose from two primary/secondary virtual ROM or stock ROM. Flashing multiple ROMs at the same time without a reboot is now possible.
Click to expand...
Click to collapse
How to check if an IMG is corrupted using MultiSystem status?
Code:
Current System IMG: Test_Rom.img
Current System DEV: [B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
When you see "/dev/block/mmcblk0p23"; it's the original system partition; so MultiSystem failed to boot Test_Rom.img, but it should be your current system.
So, the check is simple based on "Current System Device":
/dev/block/mmcblk0p23 = Stock System Partition
/dev/block/loop0 = Virtual System IMG
Note: The block device number (mmcblk0p23) may vary per device & per variant !
Click to expand...
Click to collapse
Does android do any maintenance whatsoever on stored data within /data or external sd? So if I have an app installed on 1 system and not on another system will android see it and clear the data?
No, all storage partitions are shared between ROMs. If you installed an app, it'll be availabe for all of them. Since on locked devcies we're limited to stock manufacturer-based ROMs, this makes the switch between ROMs very convinient (you don't have to worry about your changes/data/setup & storage space on the another ROM; all ROMs share everything except system). However, you should make regular backups in case a virtual ROM (probably with unsafe mods) results in bootloop due to your user data. In this case, it's safe to wipe data & selectively restore apps/data from backup(s). Another advantage of sharing all storage partitions is that your messages/emails/etc received on a virtual ROM are immediated synced (actually shared) to the other ROMs.
Click to expand...
Click to collapse
Will anything like Xposed modify the virtual ROM system IMG as opposed to the stock system IMG?
When you run a Virtual System, everything incldung kernel & apps are hijacked to speak to it as the original system.
Click to expand...
Click to collapse
Can we install AOSP ROMs on locked devices?
You can only install stock/manufacturer-based ROMs on locked devices while unlocked devices can use kexec or flash the required kernel to boot any AOSP/Stock ROMs. I've got a Note 4 Developer Edition & a lot of development is planned to go there (thanks to the unlocked bootloader!) More devices will get supported including unlocked TMO & international variants after adding more features untilizing the unlocked bootloader with kexec'd kernels.
Click to expand...
Click to collapse
Are there limitations to the combinations of ROMs that can be loaded on the "stock" and "virtual" slots? Can you mix KK and LP?
Yes, if they can run on the same kernel. LP won't run on KK kernels & so, you'd have to upgrade the firmware anyway. As for running mixed compatible Android versions, this is possible but your'd have to backup your data before switching ROMs; if it cause no issues, enjoy smooth switch & if it doesn't, do factory reset in recovery & restore your data backup. Backups via MultiSystem are painless.
Click to expand...
Click to collapse
Are applications installed once for each ROM slot that has that applicaiton installed, or can I share a game across ROMs (for instance?)
Everything is shared between ROMs, which is very good for storage & for easy switching. Just make regular backups of your sensitive data.
Click to expand...
Click to collapse
How there are no performance hits while internal storage memory was much faster than any microSD technology?
Read speeds from microSD is very fast compared to write speeds & since virtual ROMs are actually a virtual read-only systems (hence, MultiSystem), they provide a high performance. Moreover, again, read speeds from EXT4 loop devices are higher compared to physical partitions. They're very bad in writing, which we don't need for the read-only "system".
Click to expand...
Click to collapse
Is there a preferred "daily driver" ROM that should be installed in the stock slot?
Uses a stock ODEXED ROM on stock slot for better stability!
Click to expand...
Click to collapse
Is it based off of Safestrap?
Short answer NO. I've been working on MultiSystem & Safestrap for ~7 months. Earlier versions of MultiSystem (called, JasmineREC) was based on Safestrap, but it failed to support newer versions of Android mainly due to TWRP changes in the graphics/UI libraries that cause segmentation fault & the stock kernel framebuffer issues. Then, I decided to find another solution. However, the basic idea of system hijack is powered by Safestrap (or 2nd-init recoveries in general) & all the work done by @Hashcode is GREATLY appreciated.
Click to expand...
Click to collapse
How can it overwrite system files while running?
MultiSystem allows you to install safe mod's or a ROM in full or OTA-like update. It's strongly recommended to install .ZIP files NOT to the current system, b/c some files can not be overwritten while running. So, you can use backup function to copy the current system & install to the new img or any of your other virtual systems. You'll have several options to activate a virtual img & reboot directly to stock system, any virtual img you've activated, quick reboot, Download/bootloader, recovery,... etc.
Click to expand...
Click to collapse
How would I benefit from it if I'm only running Stock ROM or would there be no point for me to install it?
If you run a ROM on stock system, you're vulnerable to root loss unless/untill a new rooting method for LP comes out. MultiSystem gives you the option to run safe-to-mod virtual ROMs + recovery replacement + extra features.
Click to expand...
Click to collapse
Is there a way to convert a normal ROM .ZIP into MultiSystem .IMG?
Create or copy any of your IMGs, activate it & reboot to the active IMG! Then, use FlashFire to flash the ZIP file. However, the updater-script should be safe/compatible. Some devs mount the phyical partition, which will redirect everything to it!!
For example:
Code:
mount(“ext4″, “EMMC”, “/dev/block/mmcblk0p23″, “/system”);
will mount the original system partition; while
Code:
run_program("/sbin/mount", "-t", "auto", "/system");
will mount the current system (stock or virtual). This is recommended/safe.
Click to expand...
Click to collapse
Would a KitKat ROM work with multisystem even though my stock is Lollipop?
Any ROM requires a compatible kernel & modem. So, running KK ROMs requires flashing KK firmware (namely, kernel & modem). This may work with MultiSystem on other devices, especially if the bootlpoader is unlocked. For example, I plan to add features for Note 4 DevED to allow different Android versions (including AOSP, manufacturer-based, & probably Linux systems) by utilizing kernel swapping or execution.
Click to expand...
Click to collapse
When MultiSystem comes out will it be open sourced?
Most probably, haven't decided yet!
Anyway, here's the repository on GitHub: https://github.com/hsbadr/MultiSystem
Click to expand...
Click to collapse
Click to expand...
Click to collapse
Video Tutorials
A quick preview of MultiSystem v1.0 tested on Lollipop for VZW Note 3. The video has been captured on a stable virtual ROM of JasmineROM v5.0.1. It's FULLY compatible with FlashFire on virtual/stock systems. More devices will get supported as well, after required testing.
Facebook: https://www.facebook.com/hsbadr/videos/vb.331488823689599/428178174020663
How to check if you are running a Stock/Virtual System?
There're many ways to check whether you're running a Stock or Virtual system. MultiSystem app should include this simple check at some point. That's important to avoint ruining the Stock system & keep it safe. To make it clear to NOOBZ & anyone who's requesting "another" proof even though I owe hime nothing. Very weird!
Anyway, BusyBox mountpoint applet can print the current block/device mounted to /system mountpoint by running the following command:
Code:
busybox mountpoint -n /system
The stock system is mounts the original system partition:
Code:
[B][COLOR="Red"]/dev/block/mmcblk0p23[/COLOR][/B]
while the virtual system mounts a loop device associated with a system IMG:
Code:
[B][COLOR="Blue"]/dev/block/loop0[/COLOR][/B]
Here're two videos for both stock & virtual systems...
UPDATE:
Now, you could run the following command to print the current system (stock or virtual) and the system device (physical partition or loop device):
Code:
MultiSystem status
Note: The block device number (mmcblk0p23) may vary per device & per variant !
How to repartition microSD card for MultiSystem?
You can use any tool/program for partitioning on Android, Linux, Mac, or Windows. For example, MiniTool Partition Wizard is a good partitioning tool for Windows. So, let's use it for this task. Simply, you need to follow this PDF tutorial (thanks to @carl1961). In sum:
Step 1: delete old partitions on SD card
Step 2: create FAT32 PRIMARY partition
Step 3: create EXT4 PRIMARY partition
Then, apply changes (note that the program UI may get changed in newer versions).
Notes:
This partitioning tutorial doesn't create PRIMARY partitions (it creates logical partitions). So, you need to change "Create As" from "Logical" to "Primary" when creatig a partition.
The sizes of the two partitions are arbitrary depending on number of ROMs you plan to install on the 2nd EXT4 partition.
The 1st partition (check size) is automatically detected as your external storage
In Terminal Emulator or ADB shell, check the existence of the two partitions by running the following command (in red):
Code:
[email protected]:/ # [COLOR="Red"]ls -l /dev/block/platform/msm_sdcc.3/[/COLOR]
drwxr-xr-x root root 2015-05-02 21:08 by-num
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1 -> /dev/block/mmcblk1
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p1 -> [COLOR="Blue"]/dev/block/mmcblk1p1[/COLOR]
lrwxrwxrwx root root 2015-05-02 21:08 mmcblk1p2 -> [COLOR="Blue"]/dev/block/mmcblk1p2[/COLOR]
/dev/block/mmcblk1p1 is mounted by Android as your external storage.
/dev/block/mmcblk1p2 is NOT mounted & will be your MultiSystem partition.
Click to expand...
Click to collapse
How to check microSD card partitions for MultiSystem?
You need to correctly repartition microSD card into two partitions:
exFAT or FAT32 for the 1st partition (your new external storage)
EXT4 for the 2nd partition (your MultiSystem partition)
Use the directions in this post!
You should check your 2nd SD partition in EXT4 format mounted to /MultiSystem:
check that the /MultiSystem directory exists after a reboot
check that the 2nd SD partition (/dev/block/mmcblk1p2) is mounted to /MultiSystem by running the following command in Terminal Emulator or ADB shell:
Code:
mount | grep /MultiSystem
The output should be:
Code:
/dev/block/mmcblk1p2 /MultiSystem ext4 rw,seclabel,relatime,data=ordered 0 0
How to check MultiSystem Installation?
The 1st thing to do after installing MultiSystem is to check the /MultiSystem directory & its contents (it shouldn't be empty!). Then, check usage by running the following commands in Terminal Emulator or ADB shell:
Code:
su
bash
MultiSystem
If it retuns "MultiSystem not found" or permission denied, try to use open MultiSystem app to Update Configurations & try again. If this does't fix it, try the following command:
Code:
/MultiSystem/bin/MultiSystem
This should work if you've MultiSystem binaries installed in (extracted to) /MultiSystem directory. If so, you can create a symlink in /system/xbin as follows:
Code:
mount -o remount,rw /system
ln -sv /MultiSystem/bin/MultiSystem /system/xbin/MultiSystem
Then, test it by running:
Code:
MultiSystem
The last thing before using it is to check the boot options: reboot & monitor the GREEN LED indicator for 3 seconds (change in the app) , which give you the following options:
Volume UP = Primary virtual ROM
Volume DOWN = Secondary virtual ROM
HOME KEY = Stock System
Sure, you should have installed one or more virtual ROMs.
Backup & restore or creating/installing a virtual ROM are easy as copy & paste: all img's will be at
Code:
/MultiSystem/img/system
To backup a virtual/stock system, you have many options:
Use create function to create from stock system
Use copy function to copy the IMG
Copy & paste with a new name
Use FlashFire (fully supported on virtual/stock ROMs)
...
If you've IMG mounting issues, run the following commands:
Code:
mount -o remount,rw /system
busybox ln -sv /proc/self/mounts /system/etc/mtab
If this doesn't help, try mounting from Terminal Emulator or ADB shell after selecting the IMG in MultiSystem app, by running the following command:
Code:
MultiSystem mount virtual
MultiSystem Video Tutorial
Thanks To: @Tomsgt , aka RootJunky
Don't forget to subscribe & like the video to show appreciation of his great effort & time spent in making the video :highfive::good:
If this is for VZW, why is in the Sprint area?

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