Upgraded from thumb16 to 5.1thumb0.
Maemo unbootable. Reflashed.

The dots on boot did not appear, but the keyboard light went off when I slid down the screen (and on again when I slid it back up).

Before reflashing, I tried using RescueOS to see what went wrong, and I still have no clue what happened. Upstart's "system-services" and ipconfig weren't upgraded, but I doubt there were any changes those packages that made the system bomb out.