Sure, looks cool. But if you're trying to convince anyone that BadBIOS can work as claimed, I won't be impressed until I see one system running quietnet install quietnet onto another system with a standard fresh install of Windows, Mac OS X, BSD, or Linux; using only ultrasonic communication.

Did Dragos ever claim that BadBIOS used sound as an infection mechanism rather than a side-channel for communications between systems which were already infected?

If memory serves, nothing he claimed was something that hasn't been demonstrated to be possible – only that the combination would have had to be better executed than anything we've ever seen before and, of course, the evidence never materialized. That fits with the current consensus that it was the product of some sort of mental issue – it's the superset of everything a security researcher might know to be theoretically possible.

I agree with your later comment, that it's unclear whether ultrasonic infection was actually claimed. For purposes of this thread, which started by trying to refute the position, "BadBios is totally impossible" -- the "impossible" claim the mainstream is probably referring to is infection purely by ultrasonic transmission. There's no need to prove that ultrasonic communication is plausible, or that rootkits can be installed in BIOS, EFI, harddrive controller, etc. It is impressive to see such exotic attacks actually being used, though.