Somebody known as "The Specialist" on XboxHacker.net has managed to successfully managed to play a backed up DVD without modding his firmware. The drive used was an 8050L, which uses firmware that is very much like the GDR3120, which is used in the Xbox 360.

The Specialist's work does not enable the use of linux/homebrew apps, but it is very significant because it could mean that the 360 may be cracked before we know it. From Xbox-Scene.com