The current ports of TWRP custom recovery available for the Lenovo Tab3 8, while fully functional and practical for everyday use, are outdated by a number of years and are lacking in support for later Android release versions. The codebase for TWRP v3.6.0_9-0 was compiled using the Android 9 tree for officially supported devices that shipped with Android 9 Pie or earlier versions. This build includes support for Android versions up to, and including, Android 9 Pie, and brings some notable performance optimizations, up-to-date support for various filesystem protocols, and stability improvements.
Base bumped to TWRP v3.6;
Fixed toolbox building on Android 7.1 - 7.1.2;
Edited recovery.fstab to include full partition index for backup & restore;
Fixed mounting issue on some SanDisk OTG storage devices;
Factory wipe & MTP fixes;
Implemented Pigz compression; faster & more tolerant to corruption;
Fixed restore issue with backups of /nvdata;
Those of you who are already familiar with the fundamentals of Android modding, flashing, customization, etc., will likely know the caveat. To those members who are new to flashing and modding, there are always risks involved whenever system level modifications are made to your device, or when the partitions of your device are flashed. I urge new members to read the instructions in full prior to beginning with installation. If, after fully reading everything over, you are still unclear on the instructions, post a comment outlining your questions. By proceeding further you are assuming full responsibility for your device and the operability thereof. Don't blame me if something goes wrong, but I will provide support to the best of my ability in such circumstances. Follow each step carefully and everything should go smoothly.
Installing this TWRP build is fairly straightforward and only a couple of prerequisites exist: you must have an unlocked bootloader; and you will need a laptop or PC with the SDK Platform Tools installed or, alternatively, the Minimal ADB & Fastboot Tools.
UPGRADING TWRP BUILD
In the event you already have a previous version of TWRP installed, you may upgrade simply by downloading TWRP v3.6.0_9.0 from the link below and saving the image to your tablet's internal or external storage. Next, boot your tablet into TWRP recovery mode, select Install from the home screen, tap on the Image option, navigate to the saved location of the TWRP v3.6.0_9.0 image you downloaded below, then choose Recovery from the list of partitions presented. Now swipe to commence installation. When installation completes select Reboot to Recovery. That's it.
INSTALLING TWRP FROM SCRATCH
In the event you are installing TWRP recovery to replace stock recovery, proceed with this guide. Note that this procedure can be performed on a Linux, Mac or Windows machine. This particular guide, however, focuses strictly on a Windows-based setup. Assuming that your prerequisites are taken care of, follow these instructions:
1. Download TWRP v3.6.0_9-0 from the download link below and save it in your ADB/Fastboot directory on your PC or laptop;
2. Boot your tablet into fastboot mode. This can be done via ADB by executing:
adb reboot bootloader
Or, with your device powered off, hold the Power and Volume Up buttons simultaneously until the Boot Mode menu appears on screen. Using Volume Up, navigate to Fastboot Mode and use Volume Down to select.
3. Connect your Tab3 to your PC or laptop by using the factory supplied, or a quality equivalent, micro USB to USB-A charging/syncing cable.
4. Open a command window in the path of your ADB/Fastboot directory and execute this command:
If you are properly synced, the command window will return an alphanumeric string that corresponds to your device serial number. 5. Once a proper connection has been established, execute:
fastboot flash recovery twrp.img
This command assumes that you have renamed your TWRP recovery to twrp.img. Otherwise, use TWRP's exact filename in place of twrp.img. Now boot into TWRP by executing:
fastboot boot twrp.img
The filename for TWRP applies here as well.
6. Once booted into TWRP recovery mode, take care if your device is running unmodified stock firmware, and select the option for no changes to occur to the /system partition. The unmodified stock OS implements force encryption as well as dm-verity. Even mounting the /system partition as read/write will be detected by dm-verity and will result in a perpetual boot loop. The boot loop can easily be resolved by flashing either the Magisk root script or a kernel no-verity script.
7. To ensure that the stock OS does not initiate overwriting TWRP with the stock recovery during first boot, save a copy of the TWRP image to internal or external device storage. Select Install on TWRP's home screen, select the option for Images, navigate to the twrp.img file, select it and choose the option for Recovery from the list you are given. Commence with installation.
8. If you wish to install a custom theme pack you can do that at this time or you can opt to Reboot System. Your TWRP installation is complete. To reboot your tablet from this point, use:
THANKS & MENTIONS:
First and foremost, thanks to TeamWin Recovery Project for providing the base build. Thanks to the XDA members who remain dedicated to the Lenovo Tab3 8 and its continuing development projects. Although I'm slow, I have two more projects in the works for our beloved tablets. Thank you for your patience my friends.
Please leave a comment detailing any bugs or instabilities you may encounter. I will diligently try to patch and fix any reported bugs.
Okay I think dm-veriry is to blame. If you mounted /system after installing TWRP, dm-veriry will be triggered and the device will boot loop.
You need to flash a dm-verity disabler. I'll get you a link .