The existence of the device is hardly evidence of who was responsible for creating it. The claim in question is that Arrington and crew contributed nothing to the piece of hardware in question. Michael Arrington could have built the entire thing by himself in his basement and the situation from our perspective would be the same as long as FG could get ahold of one of the devices.

I got the impression from Arrington's own writing that Fusion Garage was primarily responsible for the nuts-and-bolts tech.