I have not seen this issue at all, and I have several systems, even clusters, running 5.0 software and I can guarantee you several of them have been rebooted without issue.
I don't know of anyway to restore a backup from the "console" of either type, either a physical console like a 5540/5550 IP Console or via the serial port/SSH connection console. You can however easily reset the password for ESM if you have access to the serial port, that information is sort of public knowledge now but we still keep it kinda quiet.