Necessary Equipment: 

1) xboxhdm 1.9 (Found at xbins http://turdinc.kicks-ass.net/Msntv/ps2/xbins.htm in the directory: /XBOX/Operating Systems/linux/distributions) 

2) Torx 10 And Torx 20 Screwdrivers - To Open XBOX 

3) A Spare/Blank PC Hardrive 

4) FTP Program (AceFTP, SmartFTP etc.) 

5) A blank CD-R/W and A CD Burner 

Steps: 

1. On your xbox's evox dashboard go to system utils and select backup. While your waiting for that to finish, extract all files in xboxhdm 1.9 to your PC'S hard drive and open up the folder 'linux'. In that folder is a folder called 'eeprom'. Once the backup is complete, on your PC run the desired FTP program and access your xbox. Go to E:\ backup_linux\ and download a file called 'eeprom.bin' to the xboxhdm\linux\eeprom folder of on your PC’s hard drive. Then go to the root of your xbox and download the full folders of C:\ and E:\ to your PC's hard drive to the xboxhdm\linux folder and overwrite the ones already there. 

2. Now in the root of xboxhdm is a file named 'make-iso-win'. You must run make-iso-win and wait for it to finish once it has finished. Now burn the .iso which was created to a blank cd-r/w using nero or alcohol, dvddecrypter etc. When burning is finished shutdown pc. 

3. Take out all other hard drives and put in the hard drive you wish to make an xbox hard drive and set it to be the primary master. Boot up your PC and as it is loading press whatever button to enter your BIOS setup and set your PC to boot from CD. Now reset your PC and put the cd-r/w with the .iso you created on it, in the cd/dvd drive. You should be given a list of options. 

4. Choose Option 1 (by typing ‘1’) and press enter to boot VGA console with xbox-drive utilities (default). Type ‘xboxhd’ when it asks you for a login. Another list of options will show up, choose option 1 again (the one that says ‘Build a new Xbox HD from scratch’) and it will begin to format and write the partition table etc. If you put your C:\ and E:\ onto the CD then when it asks you about them type yes and when it asks you if you would like an F select yes, it is all pretty self explanatory. Now quit and reboot your PC. If this worked you now have a brand new nearly-usable xbox hard drive. 

5. Now for locking the hard drive. When it boot from the cd again, this time type ‘3’ and hit enter to boot linux with locking/unlocking utilities. Next, type in ‘lockhd -a’. It will now search for the eeprom on the CD and will automatically lock the hard drive. Now turn off the PC and take out the hard drive when it has finished locking. 

Now put it back in your Xbox and load up and have fun! 

If you can't figure out how to burn the cd properly in Nero or whatever, don't worry, i NEVER do it properly lol, so just use the burn feature in DVD Decrypter and it'll burn the linux.iso in the proper bootable format for you to use it. Also, if your HD is OVER 137 gigs, you'll need to format the remaining space with UnleashX for it to be available once you're finished the upgrade. 

Edit - To save some people from buying a harddrive that isn't lockable and therefore wasting their money, please visit this link for a list of lockable and therefore Xbox compatible harddrives - http://www.xbox-hq.com/html/modules.php?name=Xbox_HardDrives