[WIP]Android on Samsung Chromebook series 3 - Chromebooks

UPDATE: See second post for initial downloads of AOSP, CM , Arndale and Linaro/Arndale builds. These are very much a work in progress and may not even work. I am putting them forth for testing for the dev community to try out on their chromebooks.
These builds will be based on the latest JB builds. There is still alot of work to be done here. The AOSP builds initially have been put up. The other builds will go up as they are completed. I am working on the documentation for putting this together as a repeatable process is doable. In time there will be an installer and other goodies, but for now this will just be a very vanilla and manual process.
My goal is to get a working port of JB on the Samsung Chromebook. There has been no significant work on this front AFAIK. So I am taking it on myself to learn and try this out. Any community input would be helpful in making this work. I am fairly n00b at this but am looking to make this work.
I found some promising information. I might be able to build this using the binaries from arndaleboard which appears to mostly use the same hardware.
FYI for anyone experimenting to make this work please note that the following MUST be done for any chance of these root files to boot from SD.
SD/MMC boot
vold.fstab
* Change the sdcard0 and sdcard1 lines so that the first line is sdcard1 and the second is sdcard0.
fstab.arndale
* Change all references to mmcblk0px to mmcblk1px.
init.arndale.rc
* Change the 2 references to mmcblk0px to mmcblk1px.
mountd.conf
* Change the reference to mmcblk0 to mmcblk1
http://www.arndaleboard.org/wiki/index.php/Main_Page
http://forum.insignal.co.kr/viewtopic.php?f=6&t=62
http://forum.insignal.co.kr/viewtopic.php?f=6&t=63
Now that the rootfs part is addressed I am tackling the booting issues. Current uboot methods focus mainly on linux distro booting. Android appears to require its own ramdisk (which is in the links below) there will be some extra downloads such as a working uboot.
Once there are working versions of all the needed components working. An installer or installer script will be put together along with documentation. I may release this to a separate thread which I will post here.
Additional info on flashing the actual arndale. http://www.arndaleboard.org/wiki/ind...Flash_a_Device
Arndale is the base hardware also used on a Samsung series 3 Chromebook. Most if not all the components will work.
Additionally MANTA aka nexus 10 hardware is similarly identical and can be used with some success. I am working on compiling base builds based on CM10, AOSP, Linaro and Arndale's git.
Some more info on the bootloader
http://www.denx.de/wiki/U-Boot
http://www.chromium.org/chromium-os/...arm-chromebook
Im using this post to keep notes on what I find and build. I might edit some more to update as I find stuff. I will create a separate post if I have any success. I got two of these. I can live with bricking one if it happens. And I imagine there is a way to restore the system if needed. I figure I will figure that part out first. To avoid any mishaps and have a brick.
CREDITS: Musical_chairs for his invaluable input and resources he has linked in this post. I will update credits for other contributors once I get through the whole thread and credit all those obviously who build the original code these builds will be based on.

DISCLAIMER: For advanced users ONLY!! Not responsible if your chromebook gets bricked, struck by lightning or eaten by a pack of wild boars or attacked by crab people! Anything you do strongly recommended it be done on an SDcard to ensure easy rollbacks and no destruction of firmware.
Here are the first downloads of the rootfs and ramdisk (both of which are needed for a working android install on chromebook) These are based on AOSP. More files will be coming as I am compiling. Basic instructions on how to set up uboot will be posted above as well as how to properly flash an SDcard. This assumes you know how to get your chromebook into dev-mode. Please note this is strictly for anyone with android system experience. The system may not even boot properly at this point. This is pre-pre-alpha at this point. There is alot of work to do before it even comes close to being usable. But if you get it working, please make a DD image (instructions above) and post it for all to use and work from. FOSS means sharing and sharing means caring. This will speed up the work needed to make this work for all of us.
aosp-ramdisk.img
https://mega.co.nz/#!sZgVmIQY!M9ANXXEJYAWR0TlRxV_mC3CdEXkTKC_Tgr1PdOD0Hxo
aosp-rootfs.tar.bz2
https://mega.co.nz/#!ZNgAFYqR!HkXcLxead3Zgm7lNcUzjb0YlfzEbbogTL5CnZDuUtIA
arndale-kernel
https://mega.co.nz/#!gIQXVLRC!U_L0WSutAXdGzdqhFrlzD1ij750Q8lTlKwHVoC28C14
arndale-ramdisk.img.ub
https://mega.co.nz/#!RB4XBAjS!JtNgciYJrLL_TDmjXjnZkTouPKwAhva26b7U9zvBYA0
arndale-rootfs.tar.bz2
https://mega.co.nz/#!xJwBVALa!QnwJRjQzhC218tcjMtKnimKZE2kn73sGs8XgeC75fDU

I'm super excited that you're working on this Opieum. This would be absolute dream come true. I'd love to help out but I can't be a tester lol. After I get my next few paychecks I'd love to send a donation to you sir!

Im still working on it. Its a bit tricker than I thought to get it working. Not impossible tho. I just lack the experience and knowledge to get this up and running. I figured I could do it over the weekend lol. Humbling experience. Once I have something working that is moderatly usable I figure I will take some donations to support other types of chromebooks, for now tho I will just do this cause I want to get android working on the samsung chromebook series 3.

opieum said:
Im still working on it. Its a bit tricker than I thought to get it working. Not impossible tho. I just lack the experience and knowledge to get this up and running. I figured I could do it over the weekend lol. Humbling experience. Once I have something working that is moderatly usable I figure I will take some donations to support other types of chromebooks, for now tho I will just do this cause I want to get android working on the samsung chromebook series 3.
Click to expand...
Click to collapse
May want to wait for IO until after if Chrome and Android get close enough to jump from one to the other.
Also, I guess you could try and use the Cyanogen Mod port tool to try and get Android on it. It's what I used to try and get Ubuntu-Phone on my Nook. Nearly have it, but got the black screen of doom.

Thanks moocow, I appreciate the advice. I had not considered the Cyanogen tool. I know google IO is right around the corner but I want to see if I can get it working. Part of it is as much a technical exercise to see if I can do it as much as it is just doing it.
Do you have a link for this porting tool? I was looking for one. If its just porting from the git I guess I can do that too. I was just wondering if there was a specific tool do this with. I was not aware there actually was a tool.

I'm so excited someone is trying to make this work! I'm no dev, but I'd love to help in anyway. Subbing now.

http://wiki.cyanogenmod.org/w/Doc:_porting_intro
This might help also.
http://wiki.cyanogenmod.org/w/Development

Amazing! I wish you the best of luck on this
I've seen some great development for the ARM Chromebook over on the Linux side, so anything is possible
Hope your efforts will be fruitful
Thanks!

I'm excited to see some effort being put into this!
I don't think you need to worry about flashing procedures just yet, and I certainly would forget about messing with uboot until way later in the game. It's pretty easy to get a dual-boot setup on the chromebook, getting the files in place is way easier than it is on a typical Android device because you can write them to an sdcard from inside ChromeOS, then reboot to the sdcard. We can worry about booting Android from the internal storage later, shouldn't be too hard. And to do anything with uboot, you're going to need to physically disassemble the chromebook and remove the write protect screw/sticker, IMO it would be best to avoid that.
Maybe we should start by adapting this procedure, but putting an Android filesystem and kernel on the sdcard instead of Linux?
http://blogs.arm.com/software-enablement/848-running-linux-on-the-series-3-chromebook/

Thanks. I have been hitting wall after wall with u-boot so yea I am working on the dualboot method for now. That post is great! I had not seen it before. Bookmarked among many. Hopefully I can find the issues keeping me from making this work.

The first obstacle I am seeing is that while ChromeOS uses a pretty standard Linux kernel and no ramdisk (and that is what uboot will be looking for), Android uses a kernel and ramdisk on a /boot partition. I don't know enough about Android to know if it's possible to boot it with a different configuration, but I've got a hunch that if we're going to get Android to boot on this thing, we're going to need to do it a lot more like the Android x86 people do it than like a typical Android ROM.
Two exercises that I think will be very helpful here:
1. Install a Linux (Ubuntu, Debian, Arch, Fedora, whatever) on the sdcard of a chromebook without using a script like chrubuntu
2. Install Android x86 on a 'normal' computer.
I have almost done the first (I cheated and ended up using a script to install Ubuntu), the second I may eventually do if I can find the time.
...and like I said, I think the best approach here is going to be a x86 style Android installation, but with an arm build.
---------- Post added at 01:42 PM ---------- Previous post was at 01:27 PM ----------
...or maybe this is what we need - chainload uboot:
https://plus.google.com/117557107585466185396/posts/hVWc5EE9EK6
---------- Post added at 02:09 PM ---------- Previous post was at 01:42 PM ----------
Okay, this looks to be the official documentation on using nv-U-boot (chainloading uboot):
http://www.chromium.org/chromium-os...using-nv-u-boot-on-the-samsung-arm-chromebook

Upon further reading, I believe that this is the correct method:
1. Pack nv-U-boot as a signed kernel and dd it to a chromeos kernel partition.
2. nv-U-boot then boots Android using a typical Android boot command.
For the time being, I'm pretty sure it will be better to keep nv-U-boot and all the Android partitions on an sdcard, as it is no harder to boot from there than from the eMMc, and it's a whole lot safer to test stuff this way. Once we've got it working, we can repartition the eMMc and install everything there so it's faster and all that good stuff.
Bear in mind this is pretty much just academic at this point, I tried to chainload nv-U-boot but haven't actually gotten it to work. I'm pretty comfortable mucking around in Linux systems, but this uboot stuff is all new to me.
What I've done so far:
1. Set up partitions on my sdcard (including two kernel partitons) as per the first link I posted.
2. Got a working Lubuntu installation on the sdcard (cheated and used a chrubuntu-derived script).
3. Got a working Crouton (chrooted) Lubuntu setup on the internal storage (doesn't really apply here, though it comes in handy for some of the tools needed for manipulating files and stuff)
4. Tried the nv-U-boot image from opensuse:
http://download.opensuse.org/repositories/openSUSE:/12.2:/ARM:/Contrib:/Chromebook/standard/armv7hl/
5. Tried the nv-U-boot image from the Chromium Projects:
http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow.kpart.bz2
In both cases, the process is the same. Pack nv-U-boot as a signed kernel, something like this (both commands are run in a shell from within ChromeOS, in dev mode):
Code:
vbutil_kernel --pack newkernel --keyblock /usr/share/vboot/devkeys/kernel.keyblock --version 1 --signprivate /usr/share/vboot/devkeys/kernel_data_key.vbprivk --vmlinuz u-boot.img --arch arm
write it to the sdcard with dd, something like this (remember you can hose almost anything with dd if you point it at the wrong place, so use with care:
Code:
sudo dd if=newkernel of=/dev/mmcblk1p2
(this writes it to partiton 2 of my sdcard, partition 1 is my good Ubuntu kernel.)
I haven't seen nv-U-boot yet but I think I'm close.

musical_chairs said:
Upon further reading, I believe that this is the correct method:
1. Pack nv-U-boot as a signed kernel and dd it to a chromeos kernel partition.
2. nv-U-boot then boots Android using a typical Android boot command.
For the time being, I'm pretty sure it will be better to keep nv-U-boot and all the Android partitions on an sdcard, as it is no harder to boot from there than from the eMMc, and it's a whole lot safer to test stuff this way. Once we've got it working, we can repartition the eMMc and install everything there so it's faster and all that good stuff.
Bear in mind this is pretty much just academic at this point, I tried to chainload nv-U-boot but haven't actually gotten it to work. I'm pretty comfortable mucking around in Linux systems, but this uboot stuff is all new to me.
What I've done so far:
1. Set up partitions on my sdcard (including two kernel partitons) as per the first link I posted.
2. Got a working Lubuntu installation on the sdcard (cheated and used a chrubuntu-derived script).
3. Got a working Crouton (chrooted) Lubuntu setup on the internal storage (doesn't really apply here, though it comes in handy for some of the tools needed for manipulating files and stuff)
4. Tried the nv-U-boot image from opensuse:
http://download.opensuse.org/repositories/openSUSE:/12.2:/ARM:/Contrib:/Chromebook/standard/armv7hl/
5. Tried the nv-U-boot image from the Chromium Projects:
http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow.kpart.bz2
In both cases, the process is the same. Pack nv-U-boot as a signed kernel, something like this (both commands are run in a shell from within ChromeOS, in dev mode):
Code:
vbutil_kernel --pack newkernel --keyblock /usr/share/vboot/devkeys/kernel.keyblock --version 1 --signprivate /usr/share/vboot/devkeys/kernel_data_key.vbprivk --vmlinuz u-boot.img --arch arm
write it to the sdcard with dd, something like this (remember you can hose almost anything with dd if you point it at the wrong place, so use with care:
Code:
sudo dd if=newkernel of=/dev/mmcblk1p2
(this writes it to partiton 2 of my sdcard, partition 1 is my good Ubuntu kernel.)
I haven't seen nv-U-boot yet but I think I'm close.
Click to expand...
Click to collapse
Yea the u-boot stuff is real new to me. I have no issues either with linux its the bootloader stuff with android I am struggling with. I'm going to look at the arndale instructions as it uses similar hardware on how to load it from SDcard. The documentation there seems to show how to load the system. I already built and compiled the code from arndale seeing as it uses the exact specs needed. Since we have the ability to boot from SDcard on a chromebook this should be easily doable. The build will be the hard part. I am going to see what i can do with that method, I'm adapting from various sources. Ideally if I can come up with a simple image that can just be DDed over to a 32GB SD card that would be best for all to start and test with until a much easier method can be adapted. I had read elsewhere that the android method had been tried using the linux methods and it did not work. Hence why I havent looked as deeply into it. But I think at this point it seems like looking at this with a mixed methods might be the better approach. I'll post my results tomorrow as I am trying this out now.
UPDATE: I got some promising news. I am following this guide I have built android according to those instructions. http://www.arndaleboard.org/wiki/index.php/WiKi#How_to_Flash_a_Device (ignore the dipswitch references here as we got the ctrl-U option to boot and devmode)
The uboot install part is automated via a script which saves some time. Easy enough to break down the script to see how its done manually. The build will have 4.1.1 That said arndale provides pretty much all the tools to do this simpler. I think if we get this working then all we need to do is further automate the process OR provide an image with a simple script to image an SDcard with. Additionally I suspect (I have not confirmed) that the wifi and other components on the arndale are also the same on the chromebook.

Hmm, I wonder if the uboot from the arndale board will work on the chromebook? The chromebook's uboot doesn't have fastboot, and there's no way to interrupt it either (as in, hold down a key to access the uboot menu). BUT, if we put the arndale's uboot on the sdcard, as in, this:
http://www.arndaleboard.org/wiki/index.php/WiKi#Prepared_micro_SD.2FMMC_for_ARNDALE_bootable.
...that looks rather promising.

Yea that was the idea and portion I was looking at. I'm trying it out now to see if this will work.

I thought something similar might be done with Plop, the most awesomest boot loader in the world when Chrubuntu was first finding it's feet. Booting into a bootloader might be the answer for not just Android, but Windows 7.

But this is booting on ARM. So Win7 would not work here as there is no ARM capable version. The work now is being done for the Samsung Chromebook ARM version (series 3) which would also work on the Acer version that is also ARM based as well.

Nuh uh, Acer C7 is x86 based. RT can play on ARM, but a Chrome bootloader might be worth it.

You are correct sir on the Acer being intel. That being said. This project is to get android on the samsung chromebook (series 3) which is an arm EXYNOS 5xxx series CPU. The methods developed here would also likley apply to any other arm based books on the market.

Related

[unofficial][linux3.4][native][tarchive]ArchLinuxARM release for Nexus 10

This is not an Android project so I don't feel that posting it in the Android Development forum would be appropriate.
ArchLinuxARM for the manta (Samsung/Google Nexus 10) - Native Boot
Working:
Wi-Fi (with NetworkManager)
Audio (requires manual intervention)
Not Working:
Bluetooth
2D & 3D Accelerated Graphics
Installation (to a subfolder of the /data partition)
You will need a Terminal Emulator or ADB Shell to install.
This assumes that arch_manta_20141210_root.tar.gz is in the root of your internal storage (/data/media/0).
Code:
su
mkdir /data/local/arch
tar -C /data/local/arch -xpzvf /data/media/0/arch_manta_20141210_root.tar.gz
Booting
Since there is no workable multiboot solution for the Nexus 10 yet, you can take one of two routes to boot this thing:
Option 1: Flash the arch_boot.img to either the recovery or the boot partition of the internal flash chip. Due to risk of BRICKING if you flash to the wrong partition, I will not provide instructions here. I might make a flashable zip later on. Note that this removes access to Android.
Option 2: Use Fastboot to tethered boot the provided kernel from another computer where it is installed:
Code:
fastboot boot boot_arch_manta.img
Logging in
The username is "arch" and the password is "archlinux". Change the password ASAP.
For root, the username is "root" and the password is also "root". CHANGE THE PASSWORD ASAP!
You'll probably want to enable the On-Screen Keyboard (onboard) and set your Session to "MATE" up in the top right corner.
To make audio work after booting and logging in, run "fix_audio.sh" in a terminal.
Read Me
If you WIPE DATA, it will also WIPE OUT THIS PORT, all its applications, and any files you may have stored within it!
Downloads
root filesystem archive: https://drive.google.com/file/d/0B4WUjKii92l2Qkd6S3c3M2tDcTQ/view?usp=sharing
kernel for fastboot or flashing: https://drive.google.com/file/d/0B4WUjKii92l2UGhIWTlVam5vSk0/view?usp=sharing
Kernel Source: https://github.com/willcast/kernel_manta
Also available for:
Nexus 7 2013: http://forum.xda-developers.com/nex...fficial-archlinuxarm-release-n7-2013-t2969301
Galaxy S3 LTE: http://forum.xda-developers.com/gal...unofficial-port-archlinuxarm-release-t2969290
HP TouchPad: http://forum.xda-developers.com/hp-touchpad/other/unofficial-archlinuxarm-release-hp-t2969310
HTC HD2: http://forum.xda-developers.com/hd2-ubuntu/development/unofficial-archlinuxarm-htc-hd2-t2970483
Free space required?
Started with 5GB+ before downloading the 1.5 tar.gz, thought it will be enough but I'm supposed it wasn't cuz I'm getting "No space left in the device" although I still have 537MB free left.
Hmm, shouldn't do that. The archive itself is 4,060 MB uncompressed according to gzip -l.
Try booting it anyway, maybe? Also, perhaps I uploaded a truncated archive. I'll have to check.
Edit: Wait, you'd need upwards of 5.5 GB free to have both the archive and the extracted files on /data.
So, I deleted my nandroid backup and was able to install it. Actually it runs very well, I think even better than when ubuntu was being officially developed by canonical for the nexus 7. Of course it was easier to run because of the MultiRom solution, always wonder why Nexus 10 it's not supported, like Nexus 4, 5, 7 and even som non-nexus devices.
tavocabe said:
So, I deleted my nandroid backup and was able to install it. Actually it runs very well, I think even better than when ubuntu was being officially developed by canonical for the nexus 7. Of course it was easier to run because of the MultiRom solution, always wonder why Nexus 10 it's not supported, like Nexus 4, 5, 7 and even som non-nexus devices.
Click to expand...
Click to collapse
I don't know, honestly. After I'm done with the HD2 flash-image port of this, I'm looking at porting kexec hardboot from a random old Epic 4G kernel to my kernel_manta on github, because that's the only ready-made Exynos hardboot patch I can find through google. Then, we could boot this with a script similar to the Galaxy S III LTE port, and someone could theoretically port MultiROM, though that someone is probably not going to be me.
Thank you, Castwilliam! It run good , with some gitch on screen, but better than ubuntu phone devReview .
But when I run pacman -Syu ( update packages), reboot and it become blackscreen, try many taps in middle touch screen, intensity light of screen is something change. What wrong when update packages in pacman ?_?.
Is the booting option 2 temporary? Can I just turn off nexus and boot back to android? Can I unplug the nexus from PC while running linux?
I have no idea what I am doing here (and you probably dislike dealing with noobs flooding forums with questions right? :silly: )
Dri0m said:
Is the booting option 2 temporary? Can I just turn off nexus and boot back to android? Can I unplug the nexus from PC while running linux?
I have no idea what I am doing here (and you probably dislike dealing with noobs flooding forums with questions right? :silly: )
Click to expand...
Click to collapse
Yes, yes and yes
Hello,
This is awesome work! It booted properly, connected to a network, and programs run just fine. But as the tablet's pixel density is pretty high, it isn't too comfortable to use. I tried adding a new resolution using xrandr, but it throws something along the lines of "failed to get gamma size for display default". I've tried googling for it, but nothing worked. What can I do to resolve this?
Thanks,
Vedanth

[Q] Cooking ROMs... I still don't get it

Hello,
I'm willing to try and build a custom rom, but I've been diving through the site for a few days and I still don't get it. I believe I do have the required background to do this: programming, linux, etc. and I have wide experience as a phone user, etc. It's just that either I'm not reading what I need or the way I want it. The problem, I believe, is that all I find are guides telling me to install this and those tools and then open this and that and voila! you got your rom. But they're not explaining WHAT exactly goes into those roms, or what is expected to go there, what's the purpose of those contents, etc., and I can't really catch with that. I feel at a loss and hate wasting my time turning around for nothing.
1. I don't understand the difference between a flashable rom and one that is meant to be installed through recovery, although I can see they're different. Do they both models contain the same kind of data? Is there any restriction to what one model can contain over the other one? If so, how would I convert from one to the other? But please, don't tell me to use this or that tool. I just need the theory behind it. Something of sorts like: "You need to extract this or that from this tarball, then mount this image, then the directory tree there goes in that directory over the other model of rom"
2. update-binary: Okay I guess this is run when installing from recovery, and this takes care of installing the rom, right?wrong?. Is this a per-rom thing, per-device thing? generic? If it's per-rom, how to generate it? do I need to compile something? Is there any generic source code that can be used as a start?
3. Although I have a basic understanding of how the Linux directory tree works, I know Android works on top of a heavily modified Linux. So can you explain briefly how the directory tree works? For instance, I believe /data/data is where Android apps install to, in /system/bin or xbin I can find busybox binaries/symlinks if present. /dev and /proc look the same as in Linux. I don't know about /sys. Also how are both rom models deployed to this tree? What is basically being copied?
4. If I were to compile a kernel, where do I find the Android kernel sources? or is it just a generic Linux kernel? where can i get a basic config for the device? Last time I checked my device hadn't /proc/config.gz but maybe I could get it from another rom with it enabled or something. What toolchain and where to get it? Oh and if you know of a native arm version of gcc or whatsnot, I'd prefer that. Setting up IDEs or toolchains is a nightmare. I don't like crosscompiling. But crosscompiling or not, a directory with all needed binaries without needing to set up system variables nor other stuff, would be amazing.
I surely have a lot more questions that I can't get from the back of my mind now, and I'll have yet more as you explain. But the point of my questions was mainly trying to explain the degree of the loss I'm at, so you can assist me better.
If it looks like a foolish petition, well, that's because I'm quite stubborn and can't catch things that don't go my way. I really need to understand the basics before I can move into actually doing something. I want to build a rom for the right reasons(to me). It's not just about packing a set of apps or themes with it, but about learning and doing other stuff like trying to fix things that are not supposed to work for the device in that Android version, etc.
If you can't help, congrats for reading through here anyways But any help is greatly appreciated :good:
oxiroxt said:
Hello,
I'm willing to try and build a custom rom, but I've been diving through the site for a few days and I still don't get it. I believe I do have the required background to do this: programming, linux, etc. and I have wide experience as a phone user, etc. It's just that either I'm not reading what I need or the way I want it. The problem, I believe, is that all I find are guides telling me to install this and those tools and then open this and that and voila! you got your rom. But they're not explaining WHAT exactly goes into those roms, or what is expected to go there, what's the purpose of those contents, etc., and I can't really catch with that. I feel at a loss and hate wasting my time turning around for nothing.
1. I don't understand the difference between a flashable rom and one that is meant to be installed through recovery, although I can see they're different. Do they both models contain the same kind of data? Is there any restriction to what one model can contain over the other one? If so, how would I convert from one to the other? But please, don't tell me to use this or that tool. I just need the theory behind it. Something of sorts like: "You need to extract this or that from this tarball, then mount this image, then the directory tree there goes in that directory over the other model of rom"
2. update-binary: Okay I guess this is run when installing from recovery, and this takes care of installing the rom, right?wrong?. Is this a per-rom thing, per-device thing? generic? If it's per-rom, how to generate it? do I need to compile something? Is there any generic source code that can be used as a start?
3. Although I have a basic understanding of how the Linux directory tree works, I know Android works on top of a heavily modified Linux. So can you explain briefly how the directory tree works? For instance, I believe /data/data is where Android apps install to, in /system/bin or xbin I can find busybox binaries/symlinks if present. /dev and /proc look the same as in Linux. I don't know about /sys. Also how are both rom models deployed to this tree? What is basically being copied?
4. If I were to compile a kernel, where do I find the Android kernel sources? or is it just a generic Linux kernel? where can i get a basic config for the device? Last time I checked my device hadn't /proc/config.gz but maybe I could get it from another rom with it enabled or something. What toolchain and where to get it? Oh and if you know of a native arm version of gcc or whatsnot, I'd prefer that. Setting up IDEs or toolchains is a nightmare. I don't like crosscompiling. But crosscompiling or not, a directory with all needed binaries without needing to set up system variables nor other stuff, would be amazing.
I surely have a lot more questions that I can't get from the back of my mind now, and I'll have yet more as you explain. But the point of my questions was mainly trying to explain the degree of the loss I'm at, so you can assist me better.
If it looks like a foolish petition, well, that's because I'm quite stubborn and can't catch things that don't go my way. I really need to understand the basics before I can move into actually doing something. I want to build a rom for the right reasons(to me). It's not just about packing a set of apps or themes with it, but about learning and doing other stuff like trying to fix things that are not supposed to work for the device in that Android version, etc.
If you can't help, congrats for reading through here anyways But any help is greatly appreciated :good:
Click to expand...
Click to collapse
I am not terribly knowledgeable about all of this, but I will take a crack at it. Others can feel free to correct me.
1. "Flashing" is usually done through the recovery from a zip with an update script inside. That script is in a language called "edify". Read more about Edify Here and Here.
The only other common way that I know of installing a ROM is through fastboot in the bootloader, but that is normally only used with official factory images. Also, I think Samsung ROMs are often flashed with a proprietary program called Odin.
2. I think that the update-binary is standard across all recent devices. I think it is just an interpreter for the Edify scripting language. Old versions of android used a somewhat different scripting language and required a different file. You can probably pull the binary out of another recent zip and use that. The main thing you have to worry about is the update script (instructions for what the zip does) and the folder structure of the zip.
3. I am not confident to explain much here, but the apps and their data are stored in different places. User apps are stored in /data/app with app data stored in /data/data, I think. System apps are installed in /system/app. There is more files stored on the "sdcard" partition which can be internal or external, depending on the device.
4. Kernel sources are usually provided in the source code from whatever repo you are using. Different ROMs use different bases. Here is some info about grabbing the AOSP kernel sources with git: http://source.android.com/source/building-kernels.html
Many of the more popular ROMS have specific build instructions on their individual github pages (Cyanogen, Paranoid Android, etc), so you might what to look at those, too. Also, depending on the individual devices, there might be proprietary binaries sourced from the device or hardware manufacturers for things like camera drivers, graphics chips, etc.
If you want a walk through of the basic build process google has a tutorial. The last time I checked there seemed to be some outdated info, but it might give you a general idea of the build process. http://source.android.com/source/initializing.html
Hopefully someone more knowledgeable can give you more info, but that is all I got
synesthete said:
I am not terribly knowledgeable about all of this, but I will take a crack at it. Others can feel free to correct me.
1. "Flashing" is usually done through the recovery from a zip with an update script inside. That script is in a language called "edify". Read more about Edify Here and Here.
The only other common way that I know of installing a ROM is through fastboot in the bootloader, but that is normally only used with official factory images. Also, I think Samsung ROMs are often flashed with a proprietary program called Odin.
2. I think that the update-binary is standard across all recent devices. I think it is just an interpreter for the Edify scripting language. Old versions of android used a somewhat different scripting language and required a different file. You can probably pull the binary out of another recent zip and use that. The main thing you have to worry about is the update script (instructions for what the zip does) and the folder structure of the zip.
3. I am not confident to explain much here, but the apps and their data are stored in different places. User apps are stored in /data/app with app data stored in /data/data, I think. System apps are installed in /system/app. There is more files stored on the "sdcard" partition which can be internal or external, depending on the device.
4. Kernel sources are usually provided in the source code from whatever repo you are using. Different ROMs use different bases. Here is some info about grabbing the AOSP kernel sources with git: http://source.android.com/source/building-kernels.html
Many of the more popular ROMS have specific build instructions on their individual github pages (Cyanogen, Paranoid Android, etc), so you might what to look at those, too. Also, depending on the individual devices, there might be proprietary binaries sourced from the device or hardware manufacturers for things like camera drivers, graphics chips, etc.
If you want a walk through of the basic build process google has a tutorial. The last time I checked there seemed to be some outdated info, but it might give you a general idea of the build process. http://source.android.com/source/initializing.html
Hopefully someone more knowledgeable can give you more info, but that is all I got
Click to expand...
Click to collapse
OMG Finally some light! THANK YOU, THANK YOU, THANK YOU for all the info. I didn't get much right now, I'll need to read through your post a few times before I get it all, haha. I'll be sure to check the links too. Thank you!

[Project in Planning] "Recovery" for RemixOS and Android-x86

No worries, I am not asking if a recovery for RemixOS exists, because I know it doesn't, but i am thinking about creating some kind of recovery mode for Android-x86/ RemixOS myself. I have a rough Idea on how to achieve that, but as I am not a that experienced Developer (still learning on a lot of ends) and my free time is pretty rare, i made this thread to get some feedback, if I am maybe aiming for something way to big for myself or maybe if my Idea is totally stupid alltogether
So here is the rough outline on what I am planing for:
I would try to create a shell script or a GUI using Gambas (don't laugh too hard at me ), which extracts a zip and translates the edify script into common Linux commands and executes them. The first limitiation would be though, that stuff like Aroma won't be supported (at least not at the beginning).
This Script/Gui could be used in Any linux Environment, but I think using a lightweight Linux Distribution, like tinycore, which could be put on a seperate partition and started via Grub or be booted from a USB-Device should be the best option.
So i would appreciate your thoughts on it, and if anyone would like to help with advise or even joining in Development.. The better
http://forum.xda-developers.com/showthread.php?p=65807379
Great idea.
Don't give up, and please make it compatible with Phoenix OS as well...
---------- Post added at 12:50 AM ---------- Previous post was at 12:43 AM ----------
And how about a recovery in the style of Flashfire? (I mean an app running inside Android)
Well i thought of that too. But honestly, I don't really know how to program in Java. i can read the code, but writing some is far above my current abilities. I am okay with a bit of C, Shellscripting and Basic, so I decided for the last 2 because I think it will sufficient for what i am going to do and I can make the fastest progress with. I am Kinda favorizing the Shellscript right now, because that actually might work on Android in a Terminal as well
Failed Install Zip / Flash Zip In Recovery
Heyy guys. i have already try Philz touch recovery from Asus Zenfone 4 T00i and Extract that ramdisk then install to system. and now i just Type /sbin/recovery and press enter then i have entered recovery. and when i install zip. the message is failed to mount required partition. i have already modify recovery.fstab and the inside is /system in /dev/block/loop0 and /data in /dev/block/loop1.
Thats that bug i have when in recovery
Thanks before guys
Okay, i am sorry, i can't help with that, but it doesnt seem very convenient/flexible enough to be an actual help, because x86 devices just differ too much for example already in partition layout.

SU for Android on ChromeOS

This is a cross-post from a reddit thread I started, but this is probably a more appropriate location for it.
I have been trying to modify files in the system folder for the Android container on the Asus Flip so I can install SuperSu, but have run into some problems.
The system folder is contained in a squashfs image on the chromebook at /opt/google/containers/android/system.raw.img. Mounted squashfs images appear to not support read-write access. I have been able to unsquash the image, add the SuperSU apk to the /system/priv-app folder and su to the /system/xbin folder, and remake the image. This boots, but SuperSU force closes as soon as it starts.
To make tinkering easier, I've tried building a writable image using dd and mkfs. I placed it in a location that has rw access and modified the /etc/init/android-ureadahead.conf script which mounts it to enable rw access. Unfortunately though it won't boot. The boot logs for the android container show a litany of SELinux errors for different things that it could not set context, operation not permitted. I can post the exact log if necessary. Some googling led me to find that the SELinux security context attributes weren't being replicated in my image, so I tried mounting with context and fscontext options equal to the contexts from the original image, but I get the same problem.
If anyone has any ideas I'd be especially grateful.
lionclaw said:
This is a cross-post from a reddit thread I started, but this is probably a more appropriate location for it.
I have been trying to modify files in the system folder for the Android container on the Asus Flip so I can install SuperSu, but have run into some problems.
The system folder is contained in a squashfs image on the chromebook at /opt/google/containers/android/system.raw.img. Mounted squashfs images appear to not support read-write access. I have been able to unsquash the image, add the SuperSU apk to the /system/priv-app folder and su to the /system/xbin folder, and remake the image. This boots, but SuperSU force closes as soon as it starts.
To make tinkering easier, I've tried building a writable image using dd and mkfs. I placed it in a location that has rw access and modified the /etc/init/android-ureadahead.conf script which mounts it to enable rw access. Unfortunately though it won't boot. The boot logs for the android container show a litany of SELinux errors for different things that it could not set context, operation not permitted. I can post the exact log if necessary. Some googling led me to find that the SELinux security context attributes weren't being replicated in my image, so I tried mounting with context and fscontext options equal to the contexts from the original image, but I get the same problem.
If anyone has any ideas I'd be especially grateful.
Click to expand...
Click to collapse
Wayyyy out of my area of expertise, but here's my (completely novice) best guess.
>All Chromebooks are write-protected with a screw on the motherboard
>Putting a Chromebook in developer mode allows for some tinkering ie things like chroots, and on the asus flip, the ability to install apks from unknown sources.
>Unscrewing the write-protect screw allows for the ability to completely install a new operating system or dual boot setup.
>Maybe you need to do that before you're able to accomplish root access?
My other idea would be to try and figure out a way of doing a systemless root?
Also, total aside but since this is the only thread I've found on XDA about this device, I think chroots are theoretically possible now without the need to be in developer mode via Android apps (even without root on Android). Download the GIMP port from the Play Store to see what I'm talking about. Playing around with that for a few minutes really made me wish that it didn't use emulated mouse/keyboard in it's implementation. Also, it appears that apt-get is broken, but regardless it might interest someone out there looking for a project.
back from the dead, any progress on this?
I have been able to successfully root the Android image on my Asus Flip.
I built a blank image with dd in /usr/local, formatted it with mkfs, mounted it to a folder, mounted the original system.raw.img to a folder, copied the files across, placed *all* the SuperSU files listed as 'required' in the SuperSU update-binary in the relevant places in /system in my new image, set permissions & contexts for those files, edited arc-system-mount.conf and arc-ureadahead.conf to point to the new image and, finally, patched /etc/selinux/arc/policy/policy.30 with the SuperSU sepolicy patching tool in order to boot my rooted Android instance with selinux set to enforcing.
I have created a couple of scripts which more-or-less fully automate this procedure, which can be downloaded from nolirium.blogspot.com. Please feel free to download, open the scripts in a text editor to check them out, and try them out if you like. Only tested on Asus Flip, though.
I seem to be unable to post attachments at the moment so I will just add the descriptions here, I could probably post the entire scripts here too if anyone wants. Feel free to let me know what you think.
DESCRIPTIONS:
1-3.sh
Combines the first three scripts listed below.
01Makecontainer.sh
Creates an 900MB filesystem image in /usr/local/Android_Images, formats it, then copies Android system files therein.
02Editconf.sh
Modifies two system files: arc-system-mount.conf - changing the mount-as-read-only flag and replacing the Android system image location with a new location; and arc-ureadahead.conf - again replacing the Android system image location. Originals are renamed .old - copies of which are also placed in /usr/local/Backup.
03Androidroot.sh
Mounts the previously created Android filesystem image to a folder, and copies SuperSU files to the mounted image as specified in the SuperSU update-binary.
04SEpatch.sh
Copies an SELinux policy file found at /etc/selinux/arc/policy/policy.30 to the Downloads folder, opens an Android root shell for the SuperSU policy patching command to be entered, then copies the patched policy back to the original location. A copy of the original policy.30 is saved at /etc/selinux/arc/policy/policy.30.old and /usr/local/Backup/policy.30.old
Uninstall.sh
Removes the folder /usr/local/Android_Images and attempts to restore the modified system files arc-system-mount.conf and arc-ureadahead.conf.
ok so two questions, one do you think this would work on the Acer r13 convertable? and 2 where can I find the actual instructions/scripts
keithkaaos said:
ok so two questions, one do you think this would work on the Acer r13 convertable? and 2 where can I find the actual instructions/scripts
Click to expand...
Click to collapse
The R13 has a 64-bit Mediatek processor, right?
I have added a version for ARM64, but I haven't tested it.
You can find the instructions and scripts at nolirium.blogspot.com
ya, its a mediatek. and thanks ill go see if i can find it
---------- Post added at 03:31 AM ---------- Previous post was at 02:58 AM ----------
wow, ok. i can do this but im not sure i want to.. after reading the possible problems i may run into. Im going to be getting the G. Home in a couple weeks and i gotta keep things running smooth. This seems like going a tad too far then i need to. The other day i had action launcher going and it looked pretty damn good but i really want to try and get the action3.apk that i have put into the pri-app folder or whatever the chromebook uses i found the syst folder but cant access it. Im wondering if i make the machine writable it would work but im afraid of losing my updates, as long as i could do them manualy, i guess that would be cool. Also since im already going on... has anyone found a way to disable the dev boot screen without tinkering with the physical chromebook yet?
SuperSU on Chromebook
Hey there I love this post but unfortunately im on the mediatek (well not unfortunately cause i love it) but i do really want super su .. But i found this other post that i tried out but i am having a problem executing the scripts. When i go to run the first one, it says can not open "name of script" but the dev takes a pretty cool approach. Im still new to Chrome OS but thanks for the post and if you have any advice on executing scripts id love to hear it!! http://nolirium.blogspot.com/
I'm guessing the above post was moved from another thread...
Anyway, it turns out that zipping/unzipping the files in Chrome OS's file manager sets all the permissions to read-only. Apologies! sudo chmod+x *scriptname* should fix it...
Regarding OS updates, I actually haven't had a problem receiving auto-updates with software write-protect switched off; the main possible potential issue I could imagine arising from the procedure I outlined would involve restoring the original conf files if both sets of backups get deleted/overwritten. This seems unlikely, but in that case either manually editing the files to insert the original string (/opt/google/containers/android/system.raw.img), or doing a powerwash with forced update might be necessary in order to get the original Android container booting again.
I don't think anyone's found a way to shorten/disable the dev boot screen without removing the hardware write-protect screw - from what I've read, the flags are set in a part of the firmware which is essentially read-only unless the screw is removed. Perhaps at some point the Chrome OS devs will get fed up of reading reports from users whose relatives accidentally reset the device by pressing spacebar, and change the setup. Here's hoping.
Hey just jumpig in the thread right quick to see if these instructions are old or what-- got a chromebook pro and the notion of having to update a squashed filesystem every timeto install su seems like a pain..
Is there any kind of authoritative documentation/breakdown regarding what Chromeos is mounting where before I start breaking things? Also anyone happen to know if there's a write-protect screw anywhere in the chromebook plus/pro?
Other questions:
* adbd is running, but is not accessible from adb in the (linux) shell, which shows no devices. Do I need to access adb from another device (i'm short a usb c cable right now) or can I use adb (which is there!) on the chrome side to access adbd on the android side?
* Anyone know if adb via tcp/ip is available? Don't see it in the android settings.
Hey,
There's no real documentation AFAIK, the thing is that ARC++ is a bit of a moving target, as it's so actively being developed/reworked. For instance, with the method described earlier in the thread - it started off being possible to just swap out a file location in arc-ureadahead.conf, then they changed it to arc-setup-conf, and now, since a few CrOS versions ago, the rootfs squashfs image is mounted in a loop fashion via the /usr/sbin/arc-setup binary instead, making an overview of the setup somewhat opaque to the casual observer.
I was kind of hoping to implement a kind of hybrid systemless root style setup myself, but unfortunately I haven't really managed to find the time to sit down and fully figure out a few parts of the puzzle, in particular relating to minijail and working with namespaces. So, I'm still using the method mentioned in posts above for my rooting needs at the moment, the only significant changes being that at the moment I'm replacing /opt/google/containers.android.system.raw.img with a symlink to my writeable rooted rootfs img, and also that in recent CrOS versions the mount-as-read only and debuggable flags can be found in /etc/init/arc-setup-env ("Environment variables for /usr/sbin/arc-setup").
In general though, one can kind of get an idea of what's going on in the default setup by reading through the various /etc/init/arc-* Chrome OS upstart jobs (and their logs in /var/log). Though, like I say, things keep changing around somewhat with every CrOS update, as the implementation 'improves'. As time goes by, and the subsystem matures, it'll certainly be interesting to see what other approaches are possible relating to customizing Android on Chrome OS.
There should definitely be a write protect screw somewhere on the motherboard for the Samsungs, but so far I haven't come across any pics showing exactly which screw it is. So far, no-one seems to have been brave/foolhardy enough to fully tear down their own machine and locate the screw!
Regarding adb, on my device I found the following in arc-setup-env:
# The IPV4 address of the container.
export ARC_CONTAINER_IPV4_ADDRESS=100.115.92.2/30
adb 100.115.92.2 (in Chrome OS's shell) works fine for me, the authorisation checkbox pops up and then good to go. su works fine through adb as expected. There's also a useful little nsenter script in Chrome OS to get into the android shell; /usr/sbin/android-sh, which I've been using in my script to help patch SE linux.
I actually just updated my rooting scripts recently to support 7.1.1, though I've only tested on my own Armv7 device (Flip C100).
I'll attach them to this post in case anyone wants to take a look. There's a readme in the zip, some more details can also be found here and below
EDIT: Fixed the SE Linux issue occurring with the previous version I uploaded (it was launching daemonsu from u:r:init:s0 instead of u:r:supersu:s0).
Anyone considering giving them a spin should bear in mind that the method does involve creating a fairly large file on the device as a rooted copy of the android rootfs. (1GB for arm, 1.4GB for Intel). There's a readme in the zip but the other couple of important points are that:
a) The SuperSU 2.82 SR1 zip also needs to be downloaded and extracted to ~/Downloads on the Chromebook.
b) Rootfs verification needs to be off. The command to force this is:
Code:
sudo /usr/share/vboot/bin/make_dev_ssd.sh --remove_rootfs_verification --force --partitions $(( $(rootdev -s | sed -r 's/.*(.)$/\1/') - 1))
or the regular command to do it is:
Code:
sudo /usr/share/vboot/bin/make_dev_ssd.sh --remove_rootfs_verification
c) If, subsequent to running the scripts, there's a problem loading Android apps (e.g. after a powerwash or failed install), the command to restore the original rootfs image is:
Code:
sudo mv /opt/google/containers/android/system.raw.img.bk /opt/google/containers/android/system.raw.img
Hey this is a great response.. thanks!
Nolirum said:
Hey,
There's no real documentation AFAIK, the thing is that ARC++ is a bit of a moving target, as it's so actively being developed/reworked. For instance, with the method described earlier in the thread - it started off being possible to just swap out a file location in arc-ureadahead.conf, then they changed it to arc-setup-conf, and now, since a few CrOS versions ago, the rootfs squashfs image is mounted in a loop fashion via the /usr/sbin/arc-setup binary instead, making an overview of the setup somewhat opaque to the casual observer.
Click to expand...
Click to collapse
verity
Yeah playing with it now, I'm looking at these /etc/init/arc-*-conf files... I see that the /dev/loop# files are being set up... (more below)
Nolirum said:
I was kind of hoping to implement a kind of hybrid systemless root style setup myself, but unfortunately I haven't really managed to find the time to sit down and fully figure out a few parts of the puzzle, in particular relating to minijail and working with namespaces. So, I'm still using the method mentioned in posts above for my rooting needs at the moment, the only significant changes being that at the moment I'm replacing /opt/google/containers.android.system.raw.img with a symlink to my writeable rooted rootfs img, and also that in recent CrOS versions the mount-as-read only and debuggable flags can be found in /etc/init/arc-setup-env ("Environment variables for /usr/sbin/arc-setup").
Click to expand...
Click to collapse
Sorry not sure what you mean by "hybrid systemless root style setup"? I take it you're modifying the startup script and replaced the squashfs file in /opt... my concern about doing it was whether they were implementing some kind of dm-verity equivalent to the squashfs file to make sure it hasn't been tampered with (say, by adding /sbin/su or whatever) or whether it's safe to replace that file.. Sounds like you're saying it is? (update: I guess that's what rootfs verification does, and we can turn it off....)
Also you mean arc-setup.conf:
env ANDROID_DEBUGGABLE = 0
right?
Nolirum said:
In general though, one can kind of get an idea of what's going on in the default setup by reading through the various /etc/init/arc-* Chrome OS upstart jobs (and their logs in /var/log). Though, like I say, things keep changing around somewhat with every CrOS update, as the implementation 'improves'. As time goes by, and the subsystem matures, it'll certainly be interesting to see what other approaches are possible relating to customizing Android on Chrome OS.
Click to expand...
Click to collapse
I hadn't realized the boot was still in flux-- I'd have figured they'd worked that out by now...
Nolirum said:
There should definitely be a write protect screw somewhere on the motherboard for the Samsungs, but so far I haven't come across any pics showing exactly which screw it is. So far, no-one seems to have been brave/foolhardy enough to fully tear down their own machine and locate the screw!
Click to expand...
Click to collapse
Heh.. not gonna be me..
Nolirum said:
Regarding adb, on my device I found the following in arc-setup-env:
# The IPV4 address of the container.
export ARC_CONTAINER_IPV4_ADDRESS=100.115.92.2/30
adb 100.115.92.2 (in Chrome OS's shell) works fine for me, the authorisation checkbox pops up and then good to go. su works fine through adb as expected. There's also a useful little nsenter script in Chrome OS to get into the android shell; /usr/sbin/android-sh, which I've been using in my script to help patch SE linux.
Click to expand...
Click to collapse
Cool-- adb connect 100.115.92.2 does indeed work I was gonna use netcat to open port 5555 in chromeos and pipe it through, but looks like nc isn't here and I'm not yet ready to start changing the FS..though probably will be soon... btw any idea which partitions get overwritten when chrome it does it's updates? Will /root and /etc get overwritten, for example... would a "powerwash" overwrite it or can you get easily get into an unbootable state on these things?
It's also kind of strange that adb is listening to port 30 at that (internal?) bridge address by default witho no UI to turn it off.. and it's inaccessible from outside.. i wonder if there's an easy way to change the bridge to share the same IP as the actual interface...
Final thought-- I'd love to build that system image myself soup-to-nuts, but I can't find any "caroline" device tree set up... do you or anyone else happen to know if there's a standalone AOSP device tree for the chromebooks? It would be cool to have a mashup AOSP/lineageos if such a think could be possible-- I'm guessing chromiumos is just taking the android tree, building it and then adding it into their build... I Haven't build chromiumos for many years now so I can't even begin to imagine how this android build integrates with the whole emerge thing they had going.. but I bet it takes a while
Nolirum said:
I actually just updated my rooting scripts recently to support 7.1.1, though I've only tested on my own Armv7 device (Flip C100).
Click to expand...
Click to collapse
Cool I'll take a look at these scripts.
So I haven't yet run the scripts-- just looking through them-- I noticed the section starting:
if [ -e /etc/init/arc-setup-env ]; then
echo "Copying /etc/init/arc-setup-env to /usr/local/Backup"
This doesn't exist on the x86 CB Pro. There's an arc-setup.conf that sets up the environment variables though. It sets WRITABLE_MOUNT to 0, but then so does arc-system-mount.conf
Not sure if these are different between x86 and ARM or if it's just in the latest update.. but figured I'd let you know. Wanna throw thse scripts up on github somewhere? (Or I can do it) and we can maybe look at keeping them up to date and/or standardizing them? It wouldn't be hard to determine if it's running on ARM or x86_64 (uname -i for example)..
fattire said:
So I haven't yet run the scripts-- just looking through them-- I noticed the section starting:
if [ -e /etc/init/arc-setup-env ]; then
echo "Copying /etc/init/arc-setup-env to /usr/local/Backup"
This doesn't exist on the x86 CB Pro. There's an arc-setup.conf that sets up the environment variables though. It sets WRITABLE_MOUNT to 0, but then so does arc-system-mount.conf
Not sure if these are different between x86 and ARM or if it's just in the latest update.. but figured I'd let you know. Wanna throw thse scripts up on github somewhere? (Or I can do it) and we can maybe look at keeping them up to date and/or standardizing them? It wouldn't be hard to determine if it's running on ARM or x86_64 (uname -i for example)..
Click to expand...
Click to collapse
Oh, the arc-setup-env thing is intentional. There does appear to be another issue with the x86 version though. I've written up a detailed response to your previous post; it's in a text file at the moment so I'll copy it over and format it for posting here with quotes etc now - should only take a few minutes. Yeah, sticking them on github might be a good idea; I've been meaning to create an account over there anyway.
Yeah, so... Regarding the scripts, since I've put them up here for people to download - I should mention that the first person to test them (aside from me) has reported that something's not working right (I'm waiting for confirmation but I think he tried out the x86 version). It's likely either an error on my part when copying across from my Arm version, or perhaps something not working right with conditionals, meant to deal with the various OS versions ('if; then' statements, I mean). Once I find out more, I'll edit my earlier post...
fattire said:
Sorry not sure what you mean by "hybrid systemless root style setup"? I take it you're modifying the startup script and replaced the squashfs file in /opt... my concern about doing it was whether they were implementing some kind of dm-verity equivalent to the squashfs file to make sure it hasn't been tampered with (say, by adding /sbin/su or whatever) or whether it's safe to replace that file.. Sounds like you're saying it is?
Click to expand...
Click to collapse
Oh, sorry for being a bit vague - I just mean perhaps implementing a kind of systemless root à la Magisk/SuperSU (from what I understand of how these work) - avoiding the need to actually replace files in /system. Since I'm mainly just using su for the privileges rather than actually wanting to write to /system, I had the idea that perhaps a sort of overlay on e.g. xbin and a few other locations, rather than actually rebuilding the whole of /system, might be an interesting approach....
Yep, I've been replacing /opt/google/containers/android/system.raw.img with a symlink to my modified image lately. Works fine... I think they've been focused on just getting the apps working properly, maybe something like dm-verity is still to come.
Although, one of the cool things with Chromebooks IMO is that once the Developer Mode (virtual) switch has been flipped, the system's pretty open to being hacked around with. I think a large part of the much-trumpeted "security" of the system is thanks to the regular mode/Dev mode feature, once in Dev Mode with verified boot disabled on the rootfs, we can pretty much do what we want (I like the message that comes up in the shell when entering the first command I posted under the spoiler - it literally says "YOU ARE ON YOUR OWN!").
So yeah, with Dev Mode switched off, verified boot switched on, we can't even get into the shell (just the walled-off 'crosh' prompt), making the system indeed rather secure (but, for some of us, rather limited).
fattire said:
Also you mean arc-setup.conf:
env ANDROID_DEBUGGABLE = 0
right?
Click to expand...
Click to collapse
That's what I mean by a moving target, lol. On my device the Canary channel is at Chrome OS version 61; I think they started to move out some ARC++ (the acronym stands for Android Runtime on Chrome, version 2, if anyone's wondering, btw) environment variables to a separate file in version 60, or maybe 61. Problems with being on the more 'bleeding edge' channels include:
#Sometimes stuff gets broken as they commit experimental changes.
#Any updates sometimes overwrite rootfs customizations; the higher the channel - the more frequent the updates occur.
#Some of the stuff that gets updated, may later get reverted.
And so on...
fattire said:
I hadn't realized the boot was still in flux-- I'd have figured they'd worked that out by now...
Click to expand...
Click to collapse
Yeah you'd think so. Honestly, the more I use CrOS the more it seems like a (very polished) work-in-progress to me. Though, I guess most modern OSs are also works-in-progress though. (I don't mean the former statement in a critical way; I'm very happy that new features keep getting added to the OS - Android app support being a perfect case in point, that was a lovely surprise, greatly extending the functionality of my Chromebook).
fattire said:
Cool-- adb connect 100.115.92.2 does indeed work I was gonna use netcat to open port 5555 in chromeos and pipe it through, but looks like nc isn't here and I'm not yet ready to start changing the FS..though probably will be soon...
Click to expand...
Click to collapse
Netcat's not there but socat, which I haven't any experience with but have seen described as a "more advanced version of netcat", is listed in /etc/portage/make.profile/package.installable, meaning that adding it to CrOS is supported, and as simple as:
Code:
sudo su -
dev_install #(sets up portage in /usr/local)
emerge socat
I tried socat out and it seems to work, might be interesting to play around with.
fattire said:
btw any idea which partitions get overwritten when chrome it does it's updates? Will /root and /etc get overwritten, for example...
Click to expand...
Click to collapse
Theres a question. I forget some of the exact details now (gleaned from browsing the developer mailing lists and the documentation on chromium.org), but from what I do remember and my experiences tinkering, I can say:
The auto-update model uses kernel/rootfs pairs, e.g. at the moment my device is booting from partition 2 (KERN-A) with the rootfs being partition 3 (ROOTFS-B). My understanding is that with the next OS update pushed to my device, CrOS will download the deltas of the files to be changed, and apply the changes to partitions 4 and 5 (KERN-B and ROOTS-B), setting new kernel GPT flags (priority=, tries=, successful=), which will, post-reboot, let the BIOS know that 4 and 5 will form the new working kernel/rootfs pair. Then the following update will do the same, but with partitions 2 and 3, and so on and so forth, alternating pairs each time. It's a pretty nifty system, and I think something similar might be happening with new Android devices from version O onward (?).
So partitions 2,3,4,5 are fair game for being overwritten (from the perspective of the CrOS updater program). Partition 1, the 'stateful partition') is a bit special, in addition to a big old encrypted file containing all of the userdata (/home/chronos/ dir?), it also has some extra dirs which get overlaid on the rootfs at boot. If you have a look in /mnt/stateful/, there should also be a dir called 'dev_image', which (on a device in Dev mode) gets mounted up over /usr/local/ at boot. As I mentioned above, if you do
Code:
sudo su -
dev_install
you can then emerge anything listed in /etc/portage/make.profile/package.installable (not a great deal of stuff admittedly, compared to Gentoo), which gets installed to subdirs in /usr/local/. So I think stuff in partition 1; /mnt/stateful/, should be safe from being overwritten with an OS update. I think crouton chroots get put there by default.
Most of the other partitions don't really get used, and shouldn't get touched by the updater, here's a design doc on the disk format, and here's a Reddit post (from a Google/Chromium employee) mentioning dual booting from partitions 6 and 7.
fattire said:
would a "powerwash" overwrite it or can you get easily get into an unbootable state on these things?
Click to expand...
Click to collapse
It's not too hard to mess up the system and get it into an unbootable state, lol. The "powerwash" just seems to remove user data, mainly. If you change up (the contents of) some files in /etc, or /opt, for example, then powerwash, normally they won't get restored to their original state (unless you also change release channel).
But, as long as the write-protect screw's not been removed and the original BIOS overwritten, it's always possible to make a recovery USB in Chrome's Recovery Utility on another device, and then restore the entire disk image fresh (this does overwrite all partitions). Another thing that I did was make a usb to boot into Kali; I was experimenting with the cgpt flags on my internal drive and got it into an unbootable state, but was still able to boot into Kali with Ctrl+U, and restore the flags manually from there. (To successfully boot from USB, it was essential to have previously run the enable_dev_usb_boot or crossystem dev_boot_usb=1 command in CrOS). I understand also that the BIOS type varies with device release date and CPU architecture, and that Intel devices may have some extra potential BIOS options ('legacy boot').
fattire said:
It's also kind of strange that adb is listening to port 30 at that (internal?) bridge address by default with no UI to turn it off.. and it's inaccessible from outside.. i wonder if there's an easy way to change the bridge to share the same IP as the actual interface...
Click to expand...
Click to collapse
I think I saw something related to this on the bug tracker. If I come across any info, I'll let you know...
fattire said:
Final thought-- I'd love to build that system image myself soup-to-nuts, but I can't find any "caroline" device tree set up... do you or anyone else happen to know if there's a standalone AOSP device tree for the chromebooks? It would be cool to have a mashup AOSP/lineageos if such a think could be possible-- I'm guessing chromiumos is just taking the android tree, building it and then adding it into their build... I Haven't build chromiumos for many years now so I can't even begin to imagine how this android build integrates with the whole emerge thing they had going.. but I bet it takes a while
Click to expand...
Click to collapse
Yeah, I haven't built Chromium OS or anything, but apparently, there's an option to create a 'private' overlay for the build, which doesn't get synced with the public stuff.
I think that the higher-ups at Google might be still umming and ahing as to whether or not to make source code available for the Android container, it's certainly not been made public yet. Actually, I remember seeing a Reddit post from a Google/Chromium employee mentioning this.
"That article is a little misleading in terms of open source. While the wayland-server and services that communicate with the ARC++ container are open source, the actual ARC++ container is not."
Perhaps they're waiting to see how similar implementations of Android within a larger Linux setup (e.g. Anbox) fare.
There doesn't seem to be too much that differs from AOSP in the ARC++ container - a few binaries and bits and pieces linking the hardware to the container (e.g. the camera etc), maybe some stuff related to running in a container with the graphics being piped out to Wayland?, and so on.
Oh, I was searching the bug tracker for something else, and just saw this (quoted below). Looks like it might be possible to run AOSP based images on CrOS soon!
arc: Implement android settings link for AOSP image
Reported by [email protected], Today (72 minutes ago)
Status: Started
Pri: 1
Type: Bug
M-60
When ARC started without the Play Store support there is no way for user to activate Android settings. We need implement corresponded section that has
Title: Android settings:
Link: Manage android preferences:
Inner bug: b/62945384
Click to expand...
Click to collapse
Great response! I read it once and I'll read it again in more detail then will probably have questions For whatever it may be worth, my only experience with chromiumos was building the whole thing maybe 4 years ago for my original 2011 Samsung "snow" Chromebook-- and making a bootable USB (or was it an SDcard?) to run it on (with a modified firmware that did... something I can't remember.. i think it was basically a stripped down uboot and I remember adding a simple menu or something-- I think I was trying to bypass that white startupscreen or something..). However, after doing this a few times to play with it, I realized that Chromiumos without the Chrome goodies kinda sucks and I promptly forgot everything and went back to stock.
I did have it re-partitioned to run linux as a dual boot from the SD slot or something-- I remember using that cgpt thing to select the different boot modes and vaguely recall the way it would A/B the updates (which "O" is now doing)... but anyhoo I was using the armhf ubuntu releases with the native kernel and ran into all kinds of sound issues and framebuffer only was a little crappy so...
I'm gonna re-read in more detail soon and I'm sure I'll have questions-- one of which will be-- assuming that most stuff is the same on x86 vs arm, why are there two scripts? How do they differ?
ol. On my device the Canary channel is at Chrome OS version 61; I think they started to move out some ARC++ (the acronym stands for Android Runtime on Chrome, version 2, if anyone's wondering, btw) environment variables to a separate file in version 60, or maybe 61.
Click to expand...
Click to collapse
This is the -env file I'm missing, I presume?
I think that the higher-ups at Google might be still umming and ahing as to whether or not to make source code available for the Android container, it's certainly not been made public yet. Actually, I remember seeing a Reddit post from a Google/Chromium employee mentioning this.
Click to expand...
Click to collapse
It looks from the response that the gapps portion might be what's in question-- just like ChromiumOS vs Chrome has all the proprietary bits taken out?
Here's what I'd ideally like to see:
* Rooted Android, with a toggle switch to hide su in settings a la lineage (requires a kernel patch something like this one) + settings changes from lineageos
* adb access from outside the device-- critical for quickly testing apks from android studio w/o a cable. Basically put the chromebook in a "device mode" where adb is passed through... I'm going to see if I can pipe adb through with socat as you suggest...
* what else... I dunno watch this space.
An update from a couple of guys that have tested out the scripts on Intel: It seems to be that while they are able to launch daemonsu manually (with daemonsu --auto-daemon), it apparently does not seem to be getting launched at boot.
I am waiting for some more information on this. Previously, for Marshmallow, the script was setting up the app_process hijack method in order to to launch daemonsu at boot; to support Nougat I changed it to instead create an .rc file with a service for daemonsu, and add a line to init.rc importing it. This works for me, and from what I can gather, it copied/created all files successfully on the testers devices, too, so I'm not sure at this point what the issue is there.
Edit: Fixed the issue. I updated my previous post with further details.
fattire said:
I realized that Chromiumos without the Chrome goodies kinda sucks and I promptly forgot everything and went back to stock.
Click to expand...
Click to collapse
lol yeah. True, that.
fattire said:
...assuming that most stuff is the same on x86 vs arm, why are there two scripts? How do they differ?
Click to expand...
Click to collapse
It's literally just two things that differ: the few lines where we copy the su binary over e.g.
/x86/su.pie → /system/xbin/su, daemonsu, sugote
vs
/armv7/su → /system/xbin/su, daemonsu, sugote
...and also the size of the created container. The x86 container is about 30 percent larger than the Arm one.
I had a little look at how to determine the CPU architecture programmatically on Chrome OS a while back, but couldn't seem to find a reliable way of doing this, at least not without maybe getting a bunch of people with different CrOS devices to run something like, as you mentioned, uname -i (which returns 'Rockchip' on my device, uname -m (which returns 'armv7'), or such similar, and collating the results. It was just easier to do separate versions for x86/arm, rather than introduce more conditionals (with potential for errors). I'm certainly not averse to adding a check for $ARCH, and thus standardizing the script, as long as it's reliable.
fattire said:
This is the -env file I'm missing, I presume?
Click to expand...
Click to collapse
Yep! It's just the same few envs as in the .confs, moved into a new file. I'm fairly confident that the script's conditionals deals with them OK.
fattire said:
It looks from the response that the gapps portion might be what's in question-- just like ChromiumOS vs Chrome has all the proprietary bits taken out?
Click to expand...
Click to collapse
Yeah, although the respondant there perhaps doesn't seem to realise that he's talking to a Google/Chromium dev, the way he responds. Not that that makes anything he says in his post is necessarily less valid, though.
fattire said:
Here's what I'd ideally like to see:
* Rooted Android, with a toggle switch to hide su in settings a la lineage (requires a kernel patch something like this one) + settings changes from lineageos
* adb access from outside the device-- critical for quickly testing apks from android studio w/o a cable. Basically put the chromebook in a "device mode" where adb is passed through... I'm going to see if I can pipe adb through with socat as you suggest...
Click to expand...
Click to collapse
Interesting... I agree, those would both be useful additions to the functionality of ARC++...
Quick question-- has Samsung provided the source for the GPL components (including the kernel, obviously)? I looked here but didn't see anything...? Previously the kernel was included along with the chromium source and there was like a kernel and kernel-next repository.. but this was like five years ago. I think the codename for the samsung chromebook pro is called caroline... let me quickly see if I can find a defconfig in the chromium source...
Back.. nothing here in the chromeos-4.4 branch. Nothing here either in the master branch. Maybe I'm looking in the wrong branches-- master is probably mainline kernel. Also the directories.. it took me five minutes to realize it wasn't going to be in arch/arm - force of habit I guess. I'll keep looking unless anyone knows. This "chromium-container-vm-x86" one seems to have dm_verity as an unused option. Ah, this is looking promising.
...and... here!
So it would seem that this would be built as part of the chromiumos build system, which seemed to be half gentoo five years ago building out of a chroot and was kind of a pain to set up... still, I'm guessing that since it's got that weird script to make the defconfig, what you could do is use google's chromiumos build script to make the kernel image (with whatever changes you want), then, assuming that it doesn't care if you replace the kernel, just throw it over the right Kernel A/B partition and see if it boots and starts up chromeos... it's weird cuz the kernel has to do double-duty for chromeos and android.. but I bet you can just replace it and it would work fine...
I had a cursory go at building a couple of kernel modules for my Flip C100 a while back - I didn't get too far though, lol. People do seem to have had success building their own kernels and running them with Chrome OS though, as with most things I suppose it's just how much time/effort you're willing to put in.
I think I used this and maybe this, from the crouton project to guide me.
From what I remember, I just got fed up of all the arcane errors/config choices. I remember that even though I'd imported my current device config from modprobe configs, there were then such an incredibly long string of hoops/config choices to have to go through one by one, to then be confronted with various errors (different every time ISTR) that I think I just thought "screw this". I think there were some other issue with the Ubuntu version I was using at the time as well. I know that sort of stuff's kind of par for the course with kernel compilation, but I was mainly only doing it so I could edit xpad in order to get my joypad working, in the end I found a different solution.
It shouldn't be too much hassle though, in theory I guess.... Oh, also, in order to get a freshly built kernel booting up with the CrOS rootfs, in addition to the gpt flags, I think you might have to sign it, too? (just with the devkeys & vbutil_kernel tool provided on the rootfs), some info here, and here.
From what I remember, the build system would do whatever key signing was necessary.... although I do now remember you're right there was some manual step when I was building the kernel, but I can't remember if that's because of MY changes or that was just part of the build process.
I I just dug out the old VM (Xubuntu) I was using to build and, well, let's just say I'll be doing a LOT of ubuntu updates before I can even realistically look at this. I do kinda recall setting up the environment was a huge pain so I'm going to see if I can just update the 5 year old source, target the pro and just build the kernel image and see what pops out the other end. At least I won't have to deal with the cross compiler, though I think it should hopefully take care of that itself.
Interesting to see that those crouton projects have emerged (no pun intended) so I'll check them out too while ubuntu updates itself
Thanks for the github links.. I'm going to go read that wiki.
Update: Looked at it-- funny they just stripped out the chromeos-specific parts they needed rather than emerge everything which is smart. My only question is now that Android is involved, there's that script I linked to earlier that seems to say "if you want Android support you'll need these bits too"-- wonder if the same config scripts apply, and if there are any other device tree considerations as well...
I may play a bit and see how smoothly it goes.. Unfortunately I don't have unlimited time either :/
Also, please do let me know if you put the scripts on github and I can send you pull requests if I come up with anything.
Update: Finally updated like 3 major versions of ubuntu... the "depot_tools" repo had its last commit in 2013, so I updated that. Wow, this is so much clearer than previous docs... it looks like something called gclient is used now, which I configured with:
gclient config --spec 'solutions = [
{
"url": "https://chromium.googlesource.com/chromium/src.git",
"managed": False,
"name": "src",
"deps_file": ".DEPS.git",
"custom_deps": {},
},
]
'
that let me do gclient sync --nohooks --no-history ...which i think is updating the ancient source. I probably should have just started over, but anyway... we'll see what happens.
Update again: After updating with this new gclinet tool, it appears that the old repo sync method is still required as described here. That hasn't changed after all, so now I'm going to go through this old method, which will probably completely overwhelm my storage as it's downloading with history.. but anyway, in case anyone is trying this-- looks like the whole chroot/repo sync thing may still be how it's done... the /src directory described above may only be for building just the browser, not the whole OS...
...and here it is. I will have zero room to actually build anything tho, but hey.
* [new branch] release-R58-9334.B-caroline-chromeos-3.18 -> cros/release-R58-9334.B-caroline-chromeos-3.18
Note to self: use cros_sdk --enter to actually get in the chroot. Then:
~/trunk/src/scripts $ ./setup_board --board=caroline
to set up the build for caroline. Then to build:
./build_packages --board=caroline --nowithdebug
Useful links:
* Building ChromiumOS
* [URL="http://www.chromium.org/chromium-os/how-tos-and-troubleshooting/portage-build-faq"]eBuild FAQ
[/URL]

Porting AOSP to custom-built device

Hi everyone,
as title suggests, I'd like to "port" clean AOSP to be able to install and run it on the custom device.
Basically, the situation is following: I got a custom device, based on rockchip rk3288 SoC. The device currently runs Android 5.1 successfully. I'd like to update Android to version 6 (got AOSP sources and AWS builder image up and running), but the company that created Android v5 for us no longer exists.
Thus I am here to ask for advice(s) on how to proceed (or whether it even is a good idea to do that myself, given the fact that I have zero experience with Android ROMs development), possibly a step-by-step guide on what to do.
The question is, do I just find drivers for hardware components present in the device (usb hub, ethernet, etc.) and just somehow "link" those to existing sources (of AOSP) and just run the build with different parameters? Or do I need to build a whole new kernel for the given device-OS combination?
Thank you for any advice or opinion!
Well this is an interesting one. There are several routes you can take here.
If you have the kernel source code, and the source code for the drivers, you could probably build the kernel from source and use it to boot Android, however, as that's unlikely, you're looking at a more regular porting process, which usually consists of pulling the vendor blobs from the existing Android system, building AOSP/Lineage with those blobs involved, and hacking together a new ramdisk that HOPEFULLY will be compatible. It's a very long and very tedious process, but it's certainly possible.
From that you'll then get in to the debugging stage of finding out what works out of the box, you'll very well need to make changes to AOSP for it to work on that SoC.
abtekk said:
Well this is an interesting one. There are several routes you can take here.
If you have the kernel source code, and the source code for the drivers, you could probably build the kernel from source and use it to boot Android, however, as that's unlikely, you're looking at a more regular porting process, which usually consists of pulling the vendor blobs from the existing Android system, building AOSP/Lineage with those blobs involved, and hacking together a new ramdisk that HOPEFULLY will be compatible. It's a very long and very tedious process, but it's certainly possible.
From that you'll then get in to the debugging stage of finding out what works out of the box, you'll very well need to make changes to AOSP for it to work on that SoC.
Click to expand...
Click to collapse
Thanks for pointing in the right (or at least some) direction! I found some guide on porting ROMs which I followed, basically like you said. So I just replaced some files in System image. Will flash later today, so maybe I will get some results!
abtekk said:
From that you'll then get in to the debugging stage of finding out what works out of the box, you'll very well need to make changes to AOSP for it to work on that SoC.
Click to expand...
Click to collapse
So I was following this tutorial, although found some irregularities, let's say: For example, none of those 2 folders contained init.d/ directory, thus I didn't update it. Also, I haven't found META-INF folder therefore haven't updated updater-script.
Basically, when I did (or at least what I think I was doing was that I took /system partition from our current ROM, that is working on that custom device and replaced stuff in there by stuff from the new system I wanted to port. My idea from what I've read was that i took kernel (and boot/recovery) from the original, working ROM and "injected" the new system onto it. Is that correct? Is that what I needed to do? Because the problem is, I cannot boot into the system (might as well be because of Kernel version, because I am trying to port Android 6 on Kernel 3.10. which was used in the current ROM running Android 5). It looks like the device is stuck in bootloader, or "somehow doesn't know what to start" (sorry, I can't put it better), displaying only my device's logo.
When I connect it to the computer via USB cable, running adb devices shows me that device, but when I try to access shell using adb shell I got error saying that /system/bin/sh wasn't found, which made me thinking that somehow the /system partition isn't "linked" properly, like I stated in the beginning.
Was I doing everything correctly? Do I need to do something above that? (maybe do you know about some tutorial). I am trying to port AOSP 6 Android.
Thank you!

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