[GUIDE] How to dump boot image and root Nokia 3.2 / 4.2 - Nokia 4.2 Guides, News, & Discussion

If you want to repost this guide to other websites, please let me know before you repost.
For Chinese users: 中文版教程将会在dospy发布。
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So after you unlock the bootloader successfully, you definitely want to install custom ROM, or at least root the phone, right?
Here's the guide about rooting Nokia 3.2 / 4.2.
This guide could probably work on Nokia 6.2 / 7.2 in the future.
Step 1: Unlock the bootloader
https://forum.xda-developers.com/nokia-4-2/how-to/guide-how-to-unlock-bootloader-nokia-4-2-t3962402
For Nokia 3.2, you'll need to read this as well: https://forum.xda-developers.com/nokia-3-2/how-to/guide-how-to-trigger-nokia-3-2-to-edl-t3962841
Step 2: Acknowledge current slot
You have two methods.
Method 1: After USB debugging enabled, execute this command:
Code:
adb shell getprop ro.boot.slot_suffix
Method 2: Under fastboot mode, execute this command:
Code:
fastboot getvar current-slot
We assume the current slot is b.
Step 3: Trigger the phone to EDL mode again
There's a hidden command in aboot known as "fastboot reboot-emergency".
However, normal fastboot binary doesn't have that command at all, so we need to compile a binary or hack the binary.
For Windows users, I've provided the fastboot binary that can use this command, and I renamed it to edl-fastboot.exe. You can download it on the attachment below.
For macOS/Linux distro users, I'm afraid you have to fork the source code, edit related content and compile yourself.
So with this special version of fastboot binary, we can boot the phone to EDL mode directly:
Code:
edl-fastboot.exe reboot-emergency
But wait, why didn't you mention this command when you released bootloader unlock guide?
That's because, if you attempt to use this command under locked bootloader, bootloader will response "Permission denied, auth needed. " and refuse to proceed the command.
I don't know how the authentication is done yet, but it's definitely not something that average developers can access to.
Click to expand...
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Step 4: Use partition manager to dump the partition
If you've came so far when unlocking the bootloader, you have already know the great partition manager.
Still, we assume the COM port number is 8 (COM8).
When the partition list appears, find "boot_b" (or boot_a if the current slot is a), right click on it, choose "Manage Partition Data" and click "Read Data". Then fh_loader binary will dump the boot image to your PC.
For Windows users, it's located at
Code:
%AppData%\Qualcomm\QFIL\COMPORT_8
Where %AppData% is actually C:\Users\your_user_name\AppData\Roaming .
The filename looks like this: ReadData_emmc_Lun0_0x3a000_Len65536_DT_07_09_2019_13_55_54.bin
Now close the partition manager, your phone will exit EDL mode and boot normally.
If you're interested in dumping full eMMC storage, you may want to read this: https://forum.xda-developers.com/android/general/guide-how-to-dump-write-storage-t3949588
Step 5: Install Magisk Manager and patch the boot image you dumped
I think everyone who reading this guide knows where to download Magisk Manager.
Copy the boot image you dumped with QFIL to Download directory in your phone's internal storage, and rename it to boot.img for your convenience.
In case you don't know how to patch, read this guide: https://topjohnwu.github.io/Magisk/install.html#boot-image-patching
Step 6: Flash patched boot image and reinstall Magisk for ensurance
After you pulled patched boot image from your phone, reboot your phone to fastboot mode, then execute these commands:
Code:
fastboot flash boot magisk_patched.img
fastboot reboot
Note, temporarily boot method introduced back for old A/B devices like Nokia 7 Plus no longer works on Nokia 3.2 / 4.2 - it will boot your phone to Qualcomm 900E mode.
Once your phone booted to normal OS, open Magisk Manager, and reinstall Magisk and required runtime to make the root much more effective.
You may want to read this guide if you want to inherit root along with OTA update: https://topjohnwu.github.io/Magisk/tutorials.html#ota-installation
Extra info about custom rom:
I've tested PHH-Treble GSI on Nokia 4.2 and it made me disappointed.
The vendor compatibility is worse than FIH made Android Phones.
You may want to read this for more details: https://github.com/phhusson/treble_experimentations/wiki/Nokia-4.2
Next preview: Stock firmware reinstallation guide. Note, Nokia 3.2 / 4.2 are not made by FIH, so OST LA no longer works on both devices.
Special thanks:
@topjohnwu for Magisk
Wingtech for leaking prototype units

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Reserved

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not detected
my pc doesn't detect the phone when its in edl mode. before people start asking I unlocked the bootloader by enabling oem unlock in the phone settings.

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I have a TA-1156 (a 3.2 variant) that has a different mainboard layout. For quite a while, I tried in vain to bring it into EDL mode - until I just tried the fastboot command "flash unlock" which worked.
I guess I should have tried that right away as I did have the OEM unlocking option in the developer setup.
Anyway, now I'm unlocked but can't access the partitions with the QFIL partition manager. I suspect the phone expects a different programmer than prog_emmc_firehose_8937_ddr.
I can enter EDL mode easily now with the patched fastboot exe. The correct driver is active and QFIL detects the phone. However, as soon as I follow the instructions by setting the programmer, and then try to start the partition manager, the phone stops responding.
After a while, I get a "sahara" error about no reply from the phone.
I wonder if someone has a stock boot.img of the Nokia 3.2 (build 00EEA) lying around ...
Here is someone else's photo of the mainboard (I just realized that it's actually from hikari_calyx!) but on mine, the right one of the test points you marked in your 3.2 variant does not exist, so I edited it out in the photo:
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JFDee said:
Anyway, now I'm unlocked but can't access the partitions with the QFIL partition manager. I suspect the phone expects a different programmer than prog_emmc_firehose_8937_ddr.
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My guess was right. Now I'm able to reply to myself with a solution.
I tried a different prog_emmc_firehose_8937_ddr than the one provided by @hikari_calyx in the unlock thread
There is a programmer with the same name in this firmware:
sprout-015B-0-00WW-B01 .rar
It's provided by @bouyhy01 in his rooting thread.
The size of the programmer file is slightly different:
Code:
hikari_calyx: 428,936 bytes
Firmware: 428,944 bytes
Long story short: the different programmer worked in QFIL, so the partition manager worked as well, I got my own boot image, patched, flashed and had root - finally ... Thanks for all the research work, hikari_calyx and bouyhy01 !
Attached is the working programmer file, in case anyone else stumbles upon the same problem. By the way, my phone has the October security patch installed which is currently the latest available.
View attachment prog_emmc_firehose_8937_ddr_from_fw.zip
.

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JFDee said:
Here is someone else's photo of the mainboard (I just realized that it's actually from hikari_calyx!) but on mine, the right one of the test points you marked in your 3.2 variant does not exist, so I edited it out in the photo:
View attachment 4867461
Click to expand...
Click to collapse
I guess the only point can be connected to the ground, for example, the RF shield is grounded.
JFDee said:
Attached is the working programmer file, in case anyone else stumbles upon the same problem. By the way, my phone has the October security patch installed which is currently the latest available.
View attachment 4869373
.
Click to expand...
Click to collapse
Thanks for info. Mine Nokia 3.2 is a prototype unit, so I don't know the situation of other versions of Nokia 3.2.

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Hello, I have tried this manual for rooting Nokia 4.2 with last security update of 5th of November. After 5 step (flashing patched boot image) my phone try to reboot and then asked for factory reset (Can't load android system - Your data may be corrupt). After making factory reset there were no root at all.
What can i do next ?
PS. It's strange enough when i download boot_b image it was 63.4 Mb snd when i have patched it by Magisk manager - the size od magisk_patched.img became 10.2 Mb