Got a hard-modded xbox with an LPC based SST 49LF020 chip which I'm told is most likely a cheapmod chip. I have formatted the hard drive to get rid of the original user's old programs, games, and Seinfeld episodes, and now I am stuck with error 21, with no disc booting. In hindsight, I probably should have followed the advice of Auto-Installer, and should not have nuked the storage, but we're past that point. My only hope now is to reconfigure the hard drive with my PC. Wish me luck.