Today I flashed a modern Android version onto Lenovo Tab M8 FHD (TB-8705F) (and I can't get it to work)
FOLLOW THESE INSTRUCTIONS AT YOUR OWN PERIL. I HAVE NO IDEA WHAT I AM DOING.
DON'T DO THIS IF YOU'RE NOT OKAY WITH POTENTIALLY BRICKING YOUR DEVICE.
I AM NOT RESPONSIBLE FOR DAMAGE CAUSED TO YOUR DEVICE, YOUR DEVICE NOT WORKING, ETC.
I recommend doing this from Debian, if you try it. Note that fastboot -w doesn't work on Debian, so you'll need do a factory reset using Recovery Mode instead!
You start by following Google's insructions for unlocking the bootloader on recent devices.
Then, because the device is compliant with Project Treble, you can use a Generic System Image on the device.
Google provides official Generic System Images, but the Android 13 and Android 14 ones don't work on this tablet (and, it seems, many other devices).
There's another project, called Treble Droid, which provides builds that have patches to work better on various devices. Their Android 14 image doesn't work on this tablet currently, but their Android 13 image does.
Download on the Debian system, and run all future commands from that directory.
Now it's time to, hopefully, unlock the tablet's bootloader:
1. Turn off the tablet
2. Enter FASTBOOT mode by holding the power and volume down buttons until the device vibrates. It should say "FASTBOOT mode" on the screen.
3. Install adb, fastboot, and all the things they depend on:
apt install adb fastboot
5. Start the unlock process by running:
fastboot flashing unlock
Now it's time to install it and prepare the device for use:
1. Flash the image:
fastboot flash system system.img
fastboot reboot recovery
5. Select "Wipe cache partition", and then confirm.
5. Reboot.
IF THAT DOESN'T WORK, TRY THIS
You may need the vbmeta.img file from Google's. I had already tried flashing this before trying the TrebleDroid one which doesn't provide an equivalent, so I don't know if it's needed or not.
If you try this, download the ARM64 (no Google software) image from . Extract that ZIP file.
Then, from the directory that was extracted to:
1. Flash the vbmeta partition:
fastboot flash vbmeta --disable-verity --disable-verification vbmeta.img
fastboot reboot