I've noticed in the last month or so, that when I run 'reboot', the Pi
pretty much just hangs and never reboots. I have to manually power
cycle it to come back up. I'm using the UART for GPS NMEA, so I can't
get logs from that, but on HDMI I'm not seeing anything when I run
reboot. None of the normal shutdown messages, the screen doesn't
blank, etc. It acts like it just hard hangs.