It plugs into an intermediate "flashing box", which is some sort of hash cracking accelerator (and for some, a DRM dongle for unlock codes, actual cracking is done in the cloud)

IIRC, there was a teardown of these some time ago, and all they did was breakout the battery compartment pins to Power and USB. No real components inside other than those.

You can buy one, and solder USB to one end, and a ~4.0V power supply to the battery pins