Comment # 65 on bug 1228863 from Guillermo Perez

(In reply to Alberto Planas Dominguez from comment #64)
> (In reply to Guillermo Perez from comment #63)
> > (In reply to Alberto Planas Dominguez from comment #62)
> > > (In reply to Guillermo Perez from comment #61)
> > > 
> > > > ~> sdbootutil -v --ask-pin update-predictions
> > > > Error: Can't determine root subvolume
> > > 
> > > Do you have a default snapshot?
> > > 
> > > sudo snapper ls
> > > 
> > > This should show a list of snapshots, and one of the should be marked with
> > > "*". If this is not the case, somehow you system lacks of default subvolume.
> > 
> > No, I've got only the one reverted (marked with a - and the last one, marked
> > with +) No default snapshots.
> 
> This is the main issue in your system. sdbootutil (actually snapper) cannot
> find the default snapshot, because you do no have one. You can mark a new
> one with btrfs or snapper (snapper modify --default). Your issue is not
> really related with sdbootutil afaict

Yes, that was I thought and made a new default by rolling back (forward tbh)
and it worked.
running again the sdbootutil command got a different error then, about the new
state and the old being the same and therefore not committing the changes. I
don't know exactly because at this point I almost immediately reboot to see if
the prompt for recovery key disappeared. Which didn't.
After all of that I threw the towel and reinstalled the system.
Partially unrelated, but it would be nice if, for some next uodate, the echo
for the recovery key wouldn't be obscured, it's pretty frustrating to enter
that string and not being able to see any typos.
Anyway, thank you very much for your help, i really appreciate it.