IMPORTANT PLEASE READ FIRST!
Some games require the update to be removed for a glitch to occur.
If you are playing an updated game for the FIRST time, then decline the update when prompted. You will be signed out of Xbox Live and be playing the game off-line. After you have finished the game, you can readily download the update from Xbox Live.
If you have already been playing the game, then you need to REMOVE the update for the glitch to occur. Be warned! Removing updates affects game data. You will delete saved progress and reset missions. You could also affect other game data stored on your hard drive as "removing an update" is a universal process in which the Xbox 360 removes ALL game updates. Ask yourself if you really want to do this!
To Remove An Update
1. Click the XBOX Guide Button
2. Go to SETTINGS blade in Xbox 360 dashboard, then SYSTEM SETTINGS.
3. Scroll to MEMORY and then press the A button. Then select the drive by scrolling (if more than one) and press Y to open DEVICE OPTIONS
4. Then select CLEAR SYSTEM CACHE
5. You will be asked if you want to perform maintenance on your hard drive. Choose YES
6. To reinstall the update, just go back onto Xbox Live and re-insert the game disc.