[Thinkpad Tablet General] zippy411:
Notice! This process also completely resets your tablet! Backup all files and information.

This is just me documenting my process for rooting my tablet. I am not responsible for any damage or lost information due to the process changing, errors in execution, or mistakes in my documentation. Let me know of any errors, corrections, or updates that may need made.

Thank you to contributors to the thread linked below for the information provided that allowed me to create this more detailed root guide.

https://xdaforums.com/t/custom-rom-rooting-options-vor-tb-125fu-lenovo-tab-m10-plus-3rd-gen.4480023/

This process was completed on Model: TB125FU

Follow documentation at your own risk!

First I updated my tablet until it was the newest system update available. For me that was version "TB125FU_S000118_220927_ROW"

Step 1 - Install tablet drivers on your computer

Download drivers folder and unzip

https://xdaforums.com/attachments/android_adb_interface-zip.5741369/

Plug tablet into computer

Open Device Manager

You’ll see a line item labeled “ANDROID” with a yellow exclamation mark

Right click on it and select update drivers

Select Browse Computer and navigate to the unzipped driver folder

Make sure the Include Subfolders box is checked and select Next

This will install the drivers for the tablet

Step 2 - Unlock your tablet for usb debugging

Open settings on your tablet

Search for “build”

Click “Build Number”

Click the Build Number box seven times to unlock developer options

Close and reopen the settings app

Under System there is now a Developer options, open it

Toggle the selections for OEM Unlocking and USB debugging

Step 3 - Obtain boot.img

Download and install Lenovo LSMA

https://support.lenovo.com/us/en/downloads/ds101291-rescue-and-smart-assistant-lmsa

plug your tablet into the computer

run program, select rescue

check the allow USB debugging popup on your tablet

select tablet in the LSMA program and select the allow popups on your tablet

select Download when it shows the firmware for your tablet

DO NOT CLICK START RESCUE

close the program when it finishes downloading the ROM

The ROM will download to C:\ProgramData\RSA\Download\RomFiles

Make sure ROM folder name matches the current system update version on your tablet

Copy from the downloaded ROM folder “boot.img” to your tablet

Step 4 - Modify boot.img

Download Magisk apk from the official Github page

https://github.com/topjohnwu/Magisk/releases

install APK on your tablet

open Magisk

Select Install

Select “Select and Patch a File”

Navigate to the location you copied the boot.img file and select the file

Select “Let’s Go”

Wait for flashing lot to say “All done” indicating it modified the boot.img file

Transer modified file to your computer, for me it was called “magisk_patched-25200_rgIWh.img” I then renamed it “magisk_patched.img” to make future typing commands shorter

Step 5 - Unlock bootloader and flash modified boot.img

Download Minimal ADB and Fastboot Tools

I chose to download the portable version

https://xdaforums.com/t/tool-minimal-adb-and-fastboot-2-9-18.2317790/

unzip folder

Place the modified .img file in this folder as well

Navigate to this folder, right click and launch a Command Prompt

Plug in your tablet to your computer if it isn’t already

Type “adb devices” to confirm your computer sees your tablet

Type “adb reboot bootloader” this should reboot your tablet into fastboot

Type “fastboot devices” to confirm the computer sees your tablet

Type “fastboot flashing unlock” read the instructions on screen which will tell you to press the volume up button (volume button closest to power button) to unlock bootloader.

Press the volume up button, It will say it was successful, wait a few seconds for the tablet to return to fastboot

Type “fastboot flash boot magisk_patched.img” and when you hit enter you should see a transferring status on your tablet (if you named your modified .img file something else, type that into the command instead)

When you see the transfer is complete type “fastboot reboot” which will restart the tablet.

The tablet should now be rooted which will completely reset the tablet. You will need to setup the tablet again and reinstall the Magisk app from the official Github. The Magisk App should now have superuser controls

You can relock the bootloader and return the tablet to factory image. IT WILL WIPE ALL DATA AGAIN!

To unroot you just reverse a couple steps.

Put the original boot.img (Make sure it is the boot.img of the same version ROM) in the Minimal ADB and Fastboot Tools folder on your computer

Navigate to this folder, right click, and launch a Command Prompt

Plug in the tablet to your computer

Type “adb reboot bootloader” this should reboot your tablet into fastboot

When the tablet reboots into fastboot type “fastboot flash boot boot.img”

When you see the transfer is complete type “fastboot flashing lock” read the instructions on screen which will tell you to press the volume up button (volume button closest to power button) to lock bootloader. Press the volume up button.

Type “fastboot reboot” which will restart the tablet

You tablet should now be back to normal.

***Note, if you relock the bootloader first it will not let you flash the original boot.img file. If you make that mistake as I did once you'll be able to manually startup recovery mode by first powering off the tablet by holding down the power button, then boot into recovery by holding the power button and the volume up button until the recovery screen appears. Then you can unlock the bootloader again.