only the bios in ram changes it's (shatowed)
from the orignal M$ bios that loaded at startup
before UDE takes over
error 6 is becouse it locked with a password different from what it expected
Hard Drive Locking: Why you cant drop just any drive in that box.
The xbox has a small chip called the EEPROM this chip hold 256 bytes which includes important non-box specific information. This includes the xbox live key, xbox region and, most importantly, the Unique HDD key (32 chr). Upon booting, this key goes through a mathematical equation with HDD-specific information; the result is the HDD password (40 chr). This password is used to unlock the hard drive, allowing the HDD to be accessed. If the drive cannot be unlocked you will get error 6(for wrong password) and 5 (for not locked).