Volume group "vgubuntu" not found
 

I've got an old Ubuntu 21.04 install on an encrypted disk that I want to upgrade. As it's no longer supported they turned off the repos a while ago so I can't do it from within the OS any more so I have to boot from a USB.

Unfortunately there's no obvious way to decrypt an encrypted volume in the gparted in the Ubuntu installer. It seems to just assume that you will always be able to erase everything. While trying to find a way to get the installer to access the filesystem there must have been a change made-though it wasn't obvious where. On boot I now get:
Booting to a live Ubuntu environment, I can successfully Open Encryption in GParted (this isn't an option in the Ubuntu installer) but the mount option is greyed out.

This makes me think that the data is intact, just inaccessible. How do I correct the volume group issue?

Possibly this helps:

https://gist.github.com/airglow923/7...c5a9f2295de532

http://old-releases.ubuntu.com/ubuntu/

Beware:

https://bugs.launchpad.net/ubuntu/+s...p/+bug/1979159

Thanks, might try upgrading via the mirrors if I can figure out what I need to do to get it to boot again.