Why does Pokemon LeafGreen on nogba crash after you use a gameshark code?

Pokemon LeafGreen on No$GBA may crash after using a GameShark code due to compatibility issues between the emulator and the code itself. Some cheats can alter game data in ways that the emulator is not programmed to handle, leading to errors and crashes. Additionally, certain codes might corrupt the game's memory or exceed the limits of what the emulator can process, resulting in instability. Always ensure you're using codes known to be compatible with the emulator for a smoother experience.