The Kaspersky report[1] states that GRAYFISH (which contains the HDD firmware reprogramming code) works on Windows NT 4.0, 2k, XP, Vista, Windows 7 and Windows 8, in both 32-bit and 64-bit builds. One can't help but to be impressed.

[1] http://25zbkz3k00wn2tp5092n6di7b5k.wpengine.netdna-cdn.com/f...