[General Topics] danj88:
I found this version of TWRP on the official Chinese Lenovo forum (original thread). The Lenovo P8 was originally released in the Chinese market, but there is now a version with an English stock ROM and full Play Store access being sold online.

The instructions I have written also work for the 4G model (TB-8703X) but you will be using a different version of TWRP (see below).

Notes:

This method installs TWRP and SuperSU without unlocking the bootloader. As such, there are some risks involved. Pay special attention to the steps labeled ''IMPORTANT'' to prevent a bootloop from occurring.

Necessary files:

QPST flash tool (use the latest version): https://androidmtk.com/download-qpst-flash-tool

Qualcomm USB driver : https://androiddatahost.com/nbyn6

TWRP:

- If you have the WiFi TB-8703F model, use TWRP-3.1.1-0821-LENOVO_P8(8703F)-CN-wzsx150-QPST.7z: http://www.mediafire.com/file/s6wpp3eic9gvp2y/TWRP-3.1.1-0821-LENOVO_P8(8703F)-CN-wzsx150-QPST.7z

- If you have the 4G TB-8703X model, use TWRP-3.1.1-0820-LENOVO_P8(8703X)-CN-wzsx150-QPST.7z: http://www.mediafire.com/file/o3qoa4hws0t7g16/TWRP-3.1.1-0820-LENOVO_P8(8703X)-CN-wzsx150-QPST.7z

Instructions:

1) Install QPST and the Qualcomm USB driver from the above links. Also extract the TWRP archive specific to your model number

2) Run QFIL (part of the QPST package), and select the build type ''Flat Build''

3) Next to ''Select Programmer'' click ''browse'' and select prog_emmc_firehose_8953_ddr.mbn (located in your TWRP folder)

4) Next to ''Select Build'' click ''Load XML'' and select rawprogram0.xml and then select patch0.xml (both located in your TWRP folder)

5) Turn your device off. Then, press and hold the volume up button and connect your device to your PC via the USB cable

6) QFIL should detect your device in 9008 mode (''Qualcomm HS-USB QDLoader 9008'' will appear at the top)

7) Click the blue ''Download'' button

8) IMPORTANT - once it has finished downloading, disconnect the device and enter TWRP by holding the volume up and power button together (it should vibrate just before loading into TWRP)

9) You will notice that TWRP is in Chinese, but we will now change the language to English. Slide the slider at the bottom all the way to the right, and click the grey button that is second to last in the right column (see here). Then, click the white globle icon at the top right (see here), and set the language to English (see here)

10) IMPORTANT - Press ''Advanced'' and then ''RM Forceencrypt''. Swipe to confirm. Now reboot into system (do not install SuperSU just yet).

11) Once it successfully boots into Android, power down the device again and enter TWRP (hold volume up + power button together)

12) Press ''Advanced'' and then ''Install SU'. Swipe to install.

13) IMPORTANT - after SU successfully installs, go back to the main menu, click ''Advanced'' and then ''RM Forceencrypt''. Swipe to confirm.

14) Reboot into system and your device should now be rooted

Findings:

I encountered a small issue with AdAway not loading initially. This was easily fixed by going into the SuperSU app and changing the setting ''Default access'' to ''grant''. After you successfully load AdAway and see the ''grant permissions'' popup, you can revert the setting back to ''Prompt'' in SuperSU.

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Stock ROM for TB-8703F, should you wish to revert back to the original recovery: https://xdaforums.com/showpost.php?p=74131339&postcount=16 (credit to [MENTION=5976373]daitalos[/MENTION])

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Special thanks to [MENTION=7350669]wzsx150[/MENTION] and the L.R Team for creating this version of TWRP.