[orion731]

What mod do you have? This is important because DVD-R boot methods are different for each chip. Look at the "boot procedures for all mod-chips" sticky on this forum. If you have the no-solder or R mod chip this is what I have done in the past to get my DVD-R's to work.

Make a dummy code entitled dvd-r or something. This code doesn't have to work it just has to be clicked on and off. At the gameshark main menu, swap the gameshark disc with an original disc that has a high TOC. (GTA: Vice city, Devil may cry, or other large DVD-Rom games) Wait about 20 secs. Then go into"Select codes" , choose the dummy code and turn the code on and then off again. Hit start and choose with codes. When it tells you to swap discs, hit the X button on your controller at the same time that you hold in eject. Swap the original DVD-ROM game with the back-up. The tray should go back in after 5 secs. While you are swapping discs this last time "Updating code lists" will appear on the screen. The game should now boot.

If you don't have the no-solder chip find your chip on the sticky mentioned above and follow the boot insructions. Hope this helps and Good luck!!