How to recover from a failed os upgrade

Hi All,

I have a NUC running home assistant that wont start anymore after the os upgrade.
Is there a way to reinstall the OS but then to recover a snapshot that i think are automatically created?

Or should i remove the drive from the NUC and try to read it on my PC to save some of the config?

I am just trying to avoid a full config of everything again.

Thank you!

If you really mean an OS update and not a core update then three failed restart attempts should automatically roll back to the previous version.

Thank you, sorry i am not that across all the right terminology.
The system wont boot after an upgrade (i am not sure if OS or Core)

I see GNU GRUB with 4 options - Slot A, Slot B, Slot A rescue shell, Slot B rescue shell.
Selecting any of them results in a blank screen, no errors, nothing.

I dont get any CLI options so i am not sure how to get to snapshots other than remove the drive from the NUC and mount it on my PC and copy files out, then do a fresh install and then restore the snapshot.

Thank you!

What version did you upgrade from and to?

If it was 2023.x.x than that is a core update. If it was 9.x then that is an OS upgrade.

Yes removing the drive and mounting it on a Linux system or using LinuxReader under windows will be how you have to recover the snapshots.

To prevent this issue in future you can automate backups and copying the backup to another location. See the available options here: https://www.home-assistant.io/common-tasks/os#copying-your-backups-to-another-location