One Important Caveat
As impressive as all of Guri’s work is, they all carry one critical assumption that limits their effectiveness. For all them, Guri assumes that someone can get physical access to the air-gapped computer, and be able to successfully install malware on it.
That means most of your air gaps are safe. But it’s worth remembering that Stuxnet and other successful attacks have made use of infecting isolated computer systems, either with the use of confederates or targeted malware spread by physical media.
Nevertheless, this is still some very impressive work. Well worth the read.