Using master cheats in 2 player mode
First, you must have used the master cheats (skitch, manual, grind, special, moon gravity) in story mode. Open the game sytem and go to the browser. Click on memory card 1. Use the last stor mode file and copy it to a second Memory card. Exit out of the menu.
DO NOT TURN OFF SYSTEM!!! Close system to alow the game to boot up. Next select 2player mode. And select any characters, or park. You now have all cheats on.
However, do not return to main menu or you will lose the cheats. If this happens, turn off the system, and repeat the process again to reinstall the cheats on 2 player mode.