PROBLEM with S4 shipped two weeks ago:

Room temp: 60-70 F
Other 3 machines: Working fine
Problem: Runs for 2-3 hours, then the LCD lights up blue but blank. I have tried killing the power and then plugging it back in again, and it runs up to ~250 gH for a few minutes and then back to 0 gH/s. It is all updated. It keeps hashing momentarily at 1.8-1.9 then immediately drops to 0 gH/s.

Possibly bad sensor that thinks it's overheating? I have no idea.

What should I do? Flash firmware? Is this OK to do?