If the ISO contains a file DAY1_00.BIN or CHEATS.BIN with a date after 2008, it’s likely modified.
: Return to the Codebreaker screen and press X to start the game with the cheats side-loaded. Using Codebreaker on Original PS2 Hardware (Slim & Phat) Codebreaker 10.1 Iso Ps2l
Depending on your setup—whether you're using a physical console or an emulator—the process varies slightly. 1. On PCSX2 (PC Emulator) If the ISO contains a file DAY1_00