I have a MDD FW400 single 1.25GHz processor. It was actually the last G4 desktop. Apple sold it as a low end alternative to their new G5s. It does boot into 9.2.2, but only 9.2.2. I had a 9.2.1 install disk from back in the day and it would not boot from it. I downloaded and then neutered the 9.2.2 netboot image from Apple, and it boots to that and 10.2.8, and 10.5.8 on a different partition. Very handy/speedy for talking to my Ether/AppleTalk 68ks.