Action Replay codes

Datel’s device, and the one most people mean when they say "cheat cartridge". A code is a pair of hexadecimal words: an address to write to, and what to write there.

What a Action Replay code is

An Action Replay code names a memory address and a value. The cartridge sits between the console and the game, watches that address, and writes the value back whenever the game changes it — which is why an "infinite" code stays infinite instead of being a one-off top-up. Later revisions of the hardware encrypt their codes, so a v1 code and a v3 code for the same effect in the same game look nothing alike and cannot be swapped.

Entering one

Codes are typed into the device’s own menu before the game boots, one line at a time, and enabled per game. Most versions let you name a code and keep it in a list; almost none let you edit one once saved, so a typo means deleting it and starting again.

What goes wrong

Action Replay revisions are not compatible with each other. A code written for v1 entered into v3 writes to an address that means something entirely different in that game, and the usual result is a corrupted save rather than a visible error.