Got this dongle/cable from apple for sale.
Has a armprocessor inside
This dongle can be used with apple’s serial number reader (kanziSWD) via mac
I assume it has more hidden features, as its a little exaggerated to build such a complex thing to read SN from death boards.
When I was still in GSM-scene I was interested in such tools for reverse engineering them, you seem to learn the most from original tools.