[Thinkpad Tablet General] shnioob:
Hi, I'm a long-time lurker on these forums but recently had some success flashing a GSI and rooting the Lenovo Tab M10 Plus (FHD) (X606F) with TWRP, and wanted to share my exact steps here. This device is awesome for the price point but unfortunately not popular enough to have many guides available. The tablet is Project Treble compatible and uses A/B roms (although it is not an A/B device in terms of OTA updates). You can use the Treble Info app to confirm that the devices uses an ARM64 A/B operating system. This was tested with the CAOS 11 GSI based on Android 11; it may work on other GSIs and other Android versions but I have not tested those (NOTE: user below confirms working on Android 12). I've written this guide at a bird's-eye-view meant for users familiar with flashing.

A couple useful notes before we begin:

- Hardware force off: hold down both volume buttons + power button

- Hardware boot into bootloader: while powered off, hold volume down + power button

- Hardware boot into recovery: hold down both volume buttons + power button

- While in fastboot mode, the command `fastboot reboot recovery` does not work for me on this device. You may have to hardware boot into recovery using the hardware steps above (power off completely then hardware boot). [This command may work for some people. It does not work for my device.]

Obviously, make sure your bootloader is unlocked before starting.

1. I used Ubuntu since Windows was having trouble recognizing the device in fastboot mode; linux drivers seem to be better developed for this particular device. I used `sudo apt install android-sdk` to get the drivers. Much easier than the nonsense that you have to do on Windows to get this device to work. Unfortunately, the Lenovo rescue app is available only for Windows, so you'll need access to Windows to gain access to vbmeta.img for installing TWRP (below).

2. Install TWRP following this guide: https://xdaforums.com/t/recovery-tb...rp-3-5-x-for-lenovo-tab-m10-fhd-plus.4222887/. It is important that you follow all these steps. After flashing the recovery, you must reboot into recovery to ensure that TWRP permanently installs. If the `fastboot reboot recovery` command does not work for you, hold down the power button to power off the device, then hardware boot into TWRP by holding down both volume buttons + power button to boot into TWRP. If you do not perform this step, the device will boot normally and TWRP will be erased. After booting into TWRP, wipe -> format data.

3. In TWRP, flash CAOS 11 GSI: https://xdaforums.com/t/official-aosp-r-mod-caos11.4265059/. You can try with other GSIs - it will probably work - but I've only tested this particular one, and can attest for the stability of CAOS 11 on this device. The image you'll want is named with -arm64-bgZ. If you use another GSI, make sure to use the A/B arm64 image. CAOS 11 has gapps included, so no need to flash here; if you use another GSI that does not have, you'll need to flash the appropriate gapps yourself. You can also opt for the non-gapps download if you don't want Google spying on you.

4. (Optional/No longer necessary) In TWRP, flash to disable dm-versity: https://zackptg5.com/android.php#disverfe.

5. (Optional - many GSIs come with root) In TWRP, flash standard Magisk.zip: https://github.com/topjohnwu/Magisk. I didn't need to use Magisk-Phh.

6. Reboot system.

7. You may or may not get errors from Google Play saying that the device is not certified. Follow these steps:

- Sign into Google account on device via settings

- Download and install the Get ID app: https://f-droid.org/en/packages/makeinfo.com.getid/

- Open the app and Copy Google Service Framework Key

- Go to https://www.google.com/android/uncertified/

- Sign in and paste the copied value to it, register

- Reboot (this actually took me a few tries to get working, I believe the key is to make sure you're signed into your Google account)

- Google Play should be working

Feel free to ask any questions here.