I recently upgraded Ubuntu to 21.10. Applying daily updates just rendered my system unusable, can't even boot into rescue mode. It says it can't find interpreter /bin/sh but when I mount the partition from another Linux image it is there, so I'm a bit miffed. If I try to boot into rescue mode it hangs with tried to kill init.

At this point I'm restoring from automatic backups which were made this morning so other than restoration time nothing of importance lost, a few music files but that's about it. But when I get it back up I'm going to have to figure out what update broke it and how to avoid breaking it again.