

The problem is probably unrelated to the firmware, and caused by some other upgrade.
After experiencing the issue, you should be able to switch to a different tty with ctrl-alt-f6 (or any other f key), log in, and check journalctl -b
for an error message. Edit: Use the End key or shift-G to scroll to the end of the journal.
I liked migadu.com as an email server, although it’s very small and doesn’t always get through the Google spam filter. It’s in switzerland which is a very good jurisdiction about privacy laws.