Let me know when you're ready, so I can remove the update block for the vuduo4kse.
When I have done so, do a software update from the menu, either unattended (with a reboot) or interactive (with a restart of enigma), and see if the box (or enigma) boots correctly with 9.1.
If not, I need to autoinstall.log from the box. And based on that I can give you the commands to fix it, if you don't want to restore the full backup.