i have never run into this exact problem, but i do know there are a few glitches with XBOXHDM 2.2s locking process. try disableing IDE autodection in your BIOS, if that doesnt work(i dont have such an option in my BIOS), try pluging the IDE into the HDD after post. in my experience this is the point after booting from the USB and selecting option 1 XBOXHDM 2.2 & SLAX, the boot script runs for a few seconds(between 5 and 10 sec) then pauses for 3-5 sec. at this pause is when you want to plug in the IDE.
i was getting "the drive is frozen" error, not the same as what is happening to you, but worth a shot.
it also acured to me that you may need to reboot XBOXHDM for it to register as locked. not sure though
This post has been edited by spliff721: Feb 17 2011, 07:12 PM