It's me again.
I'm not very sure if my method will work, but here my idea

:
- replace screen
- flash a M96 firmware file with mfgtool2 and fastboot (described here)
- set VCOM in the rom with the voltage adjustment tool, like described in this topic (Boxtor explains how to set VCOM for a M92)
- et voilą, fini!
So, now my question. Do you think that this procedure will work? Or is there a mistake in my theory? Can I take the "M96PLUS Rollback to Android 4.0.4 2015-11-10" from
this website as recovery update file? Does it contain the VCOM voltage adjustment tool?