DaddyJ, I would like to add something to your tutorial that may be usefull..
I have found out that if you time the xbox bootup (around 8 sec like DaddyJ mentioned), you will find out that it will boot up almost exactly same amount of time each and every time. By knowing this, if you time it to pull the IDE cable JUST BEFORE the MS text appears, the HD will be unlocked.
The reason for this is because if for some reason you fubar the mod and get errors, it is extreamly difficult to hotswap the drive, because as soon as the MS logo appears, it will lock the HD right away and go to the XSOD (xbox screen of death, lol). by knowing the timing, you can pull the IDE cable JUST BEFORE the logo appears and the drive is unlocked.
So, it is safe to assume that the xbox HD is fully unlocked between the points of the "X fully opened up" and the MS logo, but it is easier and safer to pull the IDE a second BEFORE the MS logo appears.
also, before you boot the xbox, start the PC and right before it goes through the IDE detection, press the "pause/Break" key (usually above the Page Up key). then start the xbox, then hotswap, then hit either spacebar or enter to get your PC to resume. (this is where hooking up a spare power connecter from the PC to the xbox HD comes in handy.)
I hope this helps those tring to hotswap a fubared softmod. It took me a short while to find this out.