Oh, it's just three or four USB stacks you have to mess up: 1) Windows (hey, they've found bugs exploitable in every Windows from 95/98 up to 7!), 2) Linux, 3/4) Phoenix/Award BIOS.
Assuming a government is the adversary (and we ALL know that the NSA sits on a very comprehensive list of exploits!), then this part is actually the easiest.