You may need to factory reset the Lenovo Tab M7 (Gen3) if you run into irrecoverable issues. Here are some ways that might work based on my experience:
The steps described here worked for me:
- First power off the tablet.
- Now keep the Volume Up, Volume Down and Power - all 3 of them pressed down until you see the Lenovo logo appear on the display. This might take 30 seconds or more.
- When the Lenovo logo appears, only let go of the Power button and continue to keep the Volume Up and Volume Down buttons pressed.
- After a few seconds, the Android Recovery menu with a list of options will appear! Let go of the Volume buttons now.
- Move up and down the items using the Volume buttons. When you come to the Wipe data/factory reset option, press the Power button to choose that. Confirm and the phone will be wiped.
- After that choose the Reboot system now option. You will reboot into a fresh tablet and will need to set up the tablet from scratch.
What does not work
There is no way to factory reset if the device is already booted into Android and you are inside a non-admin account. You need to use the physical buttons method above.
Keeping Volume Down and Power buttons pressed takes the tablet into a FASTBOOT mode. Not sure what I can do after that.
Keeping Volume Up and Power buttons pressed takes the tablet into a META mode. Not sure what I can do after that.