luckily, I did not have to unplug bad HU or board to continue to mine. Seller let me know there is firmware to allow to mine on good boards. since I was able to get machine to mine, I would not commit to trying to update firmware. My version is below. I did out of frustration do a factory reset and that was a nightmare for me. I had a hard time getting my pool back into system but it ended up being a stupid mistake on my part. looking into the manual thats on mfr site, I can say, I would not want to update firmware, afraid to make a mistake and ruin machine. good luck! I have since given seller info and waiting for them to ship me a HU.

Firmware Version21022601_4ec6bb0_5f74eef