"Codebreaker" usually refers to physical cheat cartridges like Game Genie (Galob) or GameShark (Interact/Mad Catz).
No physical cheat devices exist. Hypervisors, encrypted RAM, signed code, and kernel anti-cheat prevent hardware injection. Software mods (CFW, homebrew) are the only route—high ban risk online.
Trainers (WeMod, Cheat Happens), Cheat Engine, console commands—ubiquitous for single-player.