@guardeddon @imrehg I called LinITX who I bought it from, explained the situation. They were impeccably helpful but ultimately said, no sorry, it's out of warranty.
My only real recourse would be via them as the supplier, and they've effectively closed that door.
So I've got a bricked device going to e-waste.
Again, this makes me not want to ever buy UBNT shit again. Despite being something of an evangelist for them in the past.