I had the same issue and also could not login via ssh (the authentication no longer worked) to force a reboot from the command line.
As I also had no access to the console, the only solution was to power cycle the firewall. It then rebooted and everything worked again.
However, I have to say, this is not how an upgrade should go. :-\
As I also had no access to the console, the only solution was to power cycle the firewall. It then rebooted and everything worked again.
However, I have to say, this is not how an upgrade should go. :-\