Seeing “ERROR: device=‘PARTUUID=‘ not found. Skipping fsck.”
The parameter for PARTUUID is missing from cmdline.txt. Find the parameter in bootcmd.txt-backup and put it in cmdline.txt.
Edit:
This link covers the origin of the failure: I have no sound output through HDMI on 5.10.73-1 or 5.14 or 5.15 - #28 by Darksky
Apparently the upgrade cited installed a new cmdline.txt file but failed to copy over the PARTUUID parameter.
It is tough to search the forum for a solution when all you have is the rootfs prompt.