1. Point Dolphin to your ROM ISO directory. 2. Go to Options > Configure and click Enable Cheats. 3. Right click the game you wish to add Cheats to in the list of games and click Properties. 4. Click AR Codes or Gecko Codes depending on which you want to add. 5. Add your answer. Yes, it is an Action Replay MAX code. All others as far as I know don't work. There is no cheat to get unlimited Nitro. Why do you need cheats? Cheat Codes for Need For Speed Underground II Game Platform Dreamcast Game Boy Advance & SP Game Boy Color GameCube Nintendo 64 Nintendo DS Nintendo Wii PlayStation PlayStation2 PlayStation3 Sony PSP XBox Download Need For Speed Underground ROM for Nintendo GameCube and play it on Windows, Android or iOS. Details on all 111 Underground races, including the secrets of what you unlock, and tips on tricking out your motor. All unlockables revealed , with the secrets behind unlocking them-new body Electronic Arts' Need For Speed series takes a note from the Fast and Furious handbook with its latest release entitled Need For Speed Underground. Purchase, race, and customize 20 different licensed cars from major manufacturers such as Honda, Mitsubishi, Toyota, Volkswagen, Nissan, and more. Race other customized cars through a detailed Need for Speed Underground 2 GameCube walkthrough and guide at GameSpy - Check out the latest walkthroughs and guides for GameCube. More GameCube Cheats GameCube USB Memory Adapter Save (North America) From TwilightSlick (10/27/2017; 72KB) Underground mode completed. All cars and tracks unlocked. All parts unlocked, including some uniques. All but 4 magazine covers obtained in Underground mode. 894pZya.