So does it always get stuck at the same point ? Does it complete uploaded the other firmware ? Maybe someone knows the order the self-check does stuff. If it was a programmed chip gone bad, I'd ask Xgecu if they would sell the programmed chip.
I just got a new T48, and a little bit of something, is rolling around inside it. So I should open it up now, and see if there's a reset button or anything.
I opened it up, and broke the warranty seal for nothing, whatever was loose, already fell out. I don't see any reset button, but there's a lot of chips and SOT-23 parts in there, and a big PSU section. If you're lucky, the problem isn't in any MCU/processor.