When I was following the Textbook, and using iPrep v.006, I could not get the status to change from 0xFF, no matter what port I used. I solved this by booting the Xbox before iPrep loaded, then turning it off at the Yes/No Agreement screen. Then once I entered my S/N and hit yes to resend the MTKFlash, my status was already 0x73, and all I had to do was turn the Xbox on again and it flashed successfully.
