Re: "...need to be hard rebooted after exactly 149 hours"
That would be a big IF the engines do a restart.
I can imagine making an Atlantic crossing in a storm, run out of time, everything goes black and the flight crew fighting to reboot the computers and get engines restarted in the rain while traveling @ 425kts.
Once the engines shutdown, all heat for the control surfaces no longer exists so the leading edge of the wing, horizontal and vertical stabilizers begin to freeze. This would not be a good day.