http://forums.xbox-scene.com/index.php?s howtopic=694373
You'll want this file
http://rapidshare.com/files/299566562/XB OX360_250gb_hddss.rar
And though I'm sure the program has a readme, heres a tutorial I stole from the forum I got the hddss file from:
1) make a bootable usb stick and put on the 250 hddss.bin file, and hddhackr 1.22. (rename the .bin file to hddss).
2) shut down PC and unhoook all dvd/HDs and put in the new 250 sata drive.
3) boot PC off of USB stick
4) at command prompt type in hddhackr.exe
5) let it go through all the available sata ports and it should find the WD 2500 drive and list it.
6) select the corresponding number for it (mine was 7)
7) type in "f"
8) type in hddss
9) it should give you a new screen now
10)say yes to make the backup and name it undo.bin
11) it should ask if you want to create the 0/2/3 partitions. say yes
12) let it do its thing, and then it start flashing saying shut down computer, wait 10 seconds to restart, changes to FW will take effect after the restart.
13) shut down computer, unhook drive, hook old drives back up and finish your day.