[bighap]

This is for GS 2.01 and above but it might work.
• Boot GS2 disc 1.
• At the main screen, press the EJECT button to eject the CD tray.
• Replace the GS2 disc with an original PS2 DVD game.
• Close the CD tray (press EJECT again) and wait for 15 seconds.
• Select gameshark codes and turn on or off any code on any game.
• Press start, select with codes and press x to load game.
• A black screen will appear saying "updating codes please wait"
• Do the R-mod swap by pressing and holding eject, swap with backup, tray will close and game will load.

• NOTE: The swap must be performed within the time you see the black screen.