According to Xbox Scene, that bonus disc in the StarWars Trilogy DVD set, with the Preview Demo of the new Star Wars: Battlefront Xbox game will update your dashboard and write over key pieces of firmware, without warning.
So if you are playing this disc in a modded Xbox, you will be a victim of LucasArts' sneaky little anti-piracy move.
The 'StarWars Trilogy DVD' (video/movie DVD) has an 'Extra Special Features Disc'. If you try to launch this on your Xbox it will automaticly update your dashboard ... NO confirmation will be asked. The bonus disc has extra features including a documentary on the star wars saga, footage from the making of all three films and a preview demo of the new 'StarWars Battlefront' Xbox game (that's why there's a default.xbe, dashupdate.xbe and update.xbe on the disc).