[Lenovo Yoga Tab 3 Plus ROMs, Kernels, Recoveries, ] matshias:
WARNING!!! Be careful what you do here. One mistake and the device is soft-bricked. I take no responsibility for bricked devices, lost warranty or even OTAs not working!! Booting and/or flashing files from this post is on your own risk.

Requirements

Unlocked bootloader

Yoga Tablet 3 Plus with and without LTE (YT-X703L and YT-X703F) are supported

Known Issues

WARNING! Our device uses dm-verity (verified boot). The system partition should remain read-only. Otherwise a bootloop will occur. You can flash my modified kernel or SuperSU to resolve this but OTA's are no longer possible! You have to restore a factory image or clean system backup to receive OTAs

Potentially DRM keys are lost! Pure unlocking and rooting does not cause the issue. However, there have been reports of lost DRM keys by some unknown action. It is advised to act with caution. Losing your DRM keys can lead to issues with some apps which use DRM which could then have limited or no functionality. E.g. Netflix will only stream in SD (480p). You can check with DRM info if you still have L1 security level which means DRM keys are intact.

Download

Official TWRP for YT-X703F (Wifi): twrp.me

Official TWRP for YT-X703L (LTE): twrp.me

Instructions

Install fastboot and adb on your PC, e.g. from here

Enable developer options and in there select to unlock your bootloader by enabling OEM unlock and enable USB debugging

Connect your PC to your tablet and run

adb reboot bootloader

using adb on command line. The tablet will reboot into bootloader mode where you will only see the Lenovo logo. Now you use

fastboot oem unlock-go

to unlock. This will factory reset your device

Setup the tablet again and reboot again to the bootloader

Then run

fastboot boot twrp-3.2.1-0-yt_x703f.img

to temporarily boot into TWRP. You can also flash if you are sure ;)

Select to keep system read only when TWRP starts to avoid modification which will make OTAs impossible

Optionally flash SuperSU or Magisk in TWRP which should install system less. Keep OEM unlock enabled if you flash or modify anything

Additional Downloads

Backup of original boot, recovery and system image for YT-X703F S000936: MEGA

Modified Boot image with forceencrypt disabled and it switches off CABC fully. You need to factory reset after flashing to format data without encryption boot_yt_x703f_s000963_noforceencrypt_cabc.img (YT-X703F S000963) / boot_yt_x703l_s000963_noforceencrypt_cabc.img (YT-X703L S000963) . Use

fastboot flash boot boot_yt_x703f_s000963_noforceencrypt_cabc.img

to flash the kernel in fastboot. SuperSU or Magisk should be flashed afterwards if root is desired.

Full factory images with flash tool and instructions YT_X703F_S000689, YT_X703L_S000704, YT_X703F_S000725, YT_X703L_S000725, YT_X703F_S000734, YT_X703L_S000734, YT_X703L_S000744, YT-X703F_S000744, YT-X703L_S000963, YT-X703F_S000963 and OTA updates: MEGA (These images contain the individual boot, recovery and system images that you need to restore from any modification mentioned above)

System Updates (OTA)

In order to successfully apply Lenovo system updates after root you have to restore the original boot, recovery (if you flashed TWRP) and system partitions from your current installed version (e.g. S000744) for your variant of the tablet. This will NOT delete your apps and data but will unroot. Note that OTAs are block based and always check the contents of most of the partitions. This means that all of these partitions (except your data) have to be original and have to be on the exact same version (e.g. S000734) for the update to succeed.

See here for instructions how to restore the partitions with fastboot.

Credits

[MENTION=418122]pogo1975[/MENTION] - for providing the factory images and fixing the AV sync issue

[MENTION=6554964]launcher20[/MENTION] and [MENTION=564608]deecept[/MENTION] - for testing the LTE version

TeamWin

Changelog

v4:

Now official TWRP with version 3.0.3-0

v3:

enable full disk encryption for access to the encrypted data partition

update TWRP kernel to latest S000725 version

v2:

add support for LTE variant (YT-X703L)

add further mount points to be able to backup more data