If you have a FP5, it is virtually impossible to get stuck, lest you somehow fry the board.
You have nothing to fear once you successfully tested out your FP5.
As for the SHA digests, yes, those are expected to change randomly.
If you copy out what is known as the default bitstream, you can always get back in working order.
Technically, I think Seeed uses a special test bitstream, so “factory default” might not be desirable.