If the game (MOH) runs on your psp before you use codes, then the ISO/CSO is fine. It depends on what kind of codes you have. I'm not sure if MOH went through a patch, such as Socom did. If they did then those codes would not work. I haven't played that game in a while so I don't know if they did or not. Also, it would freeze if the code is just wrong. If the address does not match the value or something along those lines, the code would not work and you would freeze.