So how the update works is the A/V processor boots first and if it sees something on the card it puts the main CPU (the PIC32) into program mode. Kind of like plugging an Arduino into a computer.

The PIC32 isn't responding to the status/handshake request. This could be a corrupted bootloader flash or physical damage to the chip (you'd have to ask charlie if that's ever happened)

Ask Spooky if they can swap this for a board pre-flashed with Jetsons I think they have spares. Then your existing board can be reflashed or given a new chip.

I do need to revisit this board as Charlie wants me to port AMH to work on it (since they have zero remaining AMH boards)

Worst case scenario they just flash it. It doesn't have any anti consumer measures installed (though most of those chips do have the option!)