Word is out on the street that a flaw in the Xbox 360 DVD firmware may allow a hacker to install his own custom firmware in there unchecked, and as such gain full control of what the DVD will or will not accept. In practice, this would mean that the drive could gain the capability to boot backups of original game DVD?s by flashing a self-built firmware in there which ignores the mandatory disc signing.

Xboxic.com