I installed ndure earlier today with a hotswap + Xplorer360. I tried copying XBMC into E:\App via FTP, but since restarting the xbox I am now prompted with E21. I doubt the copying is related, but was the last thing I did.

I have read http://forums.xbox-scene.com/index.php?showtopic=426318, but I am unable to use xboxhdm 1.9 as I only have 1 IDE channel. I have not tried 2.2 yet as I don't have a USB drive with me currently. I have tried loading a game disk (with live), but the disk does not load.

I have tried hotswapping in Windows to use Xplorer360 again, but the drive appears locked still. It shows in diskmgmt.msc but Xplorer360 cannot find it. I do not have an eeprom backup.

If relevant, I have otherwise unmodified hardware on a 1.0 xbox. I suffer from the power on when plugged in issue due to a broken mobo trace I have yet to fix.

Any ideas on how to get my box running again?

can you force it to throw an error 12 by pulling the IDE from the back of the DVD drive and booting up?

I'll try, but then what?

EDIT: yes, the LED starts blinking red-green as soon as its turned on and goes right to E12 after the flubber animation

the HDD should unlock on an error 12.. so as soon as you see the error 12 pull the HDD IDE. then try Xplorer360 or XBOXHDM 2.2

Excellent! Worked like a charm, thanks!