You're rebooting your Kindle with a custom .bin in the userstore. Don't.
Always use the 'Update Your Kindle' link from the Settings menu. (I get that it might be tricky with a broken screen, but there's not much else we can do about it without a shell).
FYI: That's an error from the recovery updater you're seeing, which runs at boot, and expects an amazon signed recovery update, while we're providing self-signed ota updates for hacks. The ota updater throws U00N error, not N

.
EDIT: Or, apparently, updatewait can pickup custom updates, so, err, just let it sit in screensaver mode for a while, it should pick it up (too lazy to check the timers right now ;D).