Thank you for your questions as they directed me in troubleshooting.
What is SBC? You swapped or modified some hardware and forgot to mention? I don't follow, stop mixing full and standard unit again, you were working on full unit issue which is now fixed, its mining and syncing blockchains, yes/no? If yes, then problem solved, move to next problem, but do not mix everything together.
SBC, single board computer (what makes the FULL model a FULL model). To test the miner, as suggested by others in this thread, I moved the SBC to the working STANDARD unit and now that unit does not mine also. The original one which had not been mining now does, except at a very high HW error rate.
I am not a seller. To my understanding, your miner is working again, and standard unit is also working, so you have 2/2 working units. yes/no? Please explain in detail what was broken and what you fixed, because your post lack details needed before I address what you wrote.
I understand you are not the seller. That comment was not directed at you. I am interested in hearing from someone who had a similar experience helping, or someone who knows a possible solution. The issue clearly lies within the SBC.
I have contacted FutureBit via my order email and will await their reply.
Great, now I know what has happened. As n0nce said, please be careful not do damage anything else so you don't lose any warranty.
So you determined your SBC is not mining, with whatever miner board connected to its back. That's not good. Board is online, bitcoind syncing, but not mining with the board connected by GPIO. Right?
I know there are two SD card images to download, for old batch boards and new ones. Which SD card image did you try? What batch is your miner, a new one?