Mario77 it's very puzzling that a fresh install of 9.2.3 worked but then failed after restoring the backup.
Could you try installing 9.2.3 fresh again and then ssh in and post the output of
Also try using 9.2.3 with stock configuration for a bit (eg play local media, reboot) and see how that works.
Testing with another SD card may also be worth a try, maybe the one you were using is starting to fail (that would explain why boot failed after restoring backup).
so long,
Hias