Boot fails after upgrade to 21.04 - ""failed to start service for snap application"

My system hung while upgrading from 20.10 to 21.04 and wouldn't reboot. I rescued it by dropping to the command line and running sudo dpkg --configure -a, and after that everything seemed fine.

Now, when I boot up I get following:

FAILED] Failed to start Service for snap application canonical-livepatch.canonical-Livepatchd. 13.389915) usb 2-3: cannot get connectors status: reg : 0x81, wValue = 0X700, Index = 0X202, type = 0

REISUB makes it restart properly, but how do I get it to boot in the first place? Running sudo canonical-livepatch refresh doesn't work as 21.04 doesn't support Livepatch anyway.