How a cheat code actually works
A cheat code is a memory address and a value: write this there, and keep writing it. Everything else — master codes, encryption, why the same code fails on a different copy of the same game — follows from that one idea, and this page explains each of them.
What the device is doing
A cheat cartridge sits between the console and the game and watches memory. When the game writes a new value to the address the code names, the device writes the code’s value back over it. That is the whole mechanism, and it is why an "infinite ammo" code keeps working rather than topping you up once: the device is overwriting the game every frame.
Why the same code has two spellings
Later cheat devices encrypt their codes, and the encryption changed between revisions of the same product. An Action Replay v1 code and a v3 code for exactly the same effect look nothing alike, and entering one into the other writes to an address that means something different in that game. This is why a code list that does not name its device version is only usable by trial and error.
Master codes
On many PlayStation and Game Boy Advance games nothing works until one particular code points the device at the right region of memory. It does nothing you can see, so it is the code most often dropped when a list gets copied — and its absence makes every other code on the list look broken.
The honest warning about saves
A code writes into the memory the game is using. If the address is wrong for your build, the value lands in whatever is actually there, and that is frequently part of the save. The damage often does not appear until the game next writes the save back. Back up a save before running codes against a file you would be sorry to lose.
- A code is a memory address and a value to write there, rewritten every frame.
- Formats covered: Action Replay, GameShark, CodeBreaker, Gecko / Ocarina.
Questions
What is a master code, and why does nothing work without one?
On many PlayStation and Game Boy Advance games the cheat device cannot reach the game’s memory until one specific code redirects it there. That code is the master code. It produces no visible effect by itself, which is exactly why it gets left out of a list somebody copied in a hurry — and why the rest of that list then looks broken.
Why does a code that works for someone else do nothing for me?
Almost always because you are running a different build. A game’s European, North American and Japanese releases are compiled separately and lay memory out differently, and a later revision of one regional release can move it again. A code is written against one exact build, which is why every code here records its region and its revision beside it instead of only the game’s name.
Can a cheat code corrupt my save file?
Yes — and that is the honest answer rather than a disclaimer. A code writes directly into the memory the game is using. If the address is wrong for your build you are writing an arbitrary value into whatever happens to live there, often part of the save structure. The damage usually shows up later, when the game writes that state back to the cartridge or the memory card. Back up a save before using codes on a file you care about.
Why can I not retype a code with the spaces taken out?
Because the grouping is part of the code. The split between address and value, and the line breaks between separate writes, are what tell the device where one instruction ends and the next begins. This site stores every code exactly as it must be typed and copies it as a single block for that reason: reformatting is the most common way a correct code becomes a wrong one.
Do these codes work on an emulator?
Often, though not automatically. Most emulators accept raw codes for the formats their console supported, and some want them decrypted first. An emulator is also the safest place to try an unverified code, because the save is a file on your own disk that you can copy before you start.
Does Leumas host the games these codes are for?
No. Leumas supplies no games and no game files, here or on any other Leumas site. This is a reference for codes, and the deck at consoles.leumas.tech plays cartridges and discs you already own. That is the shape of both products rather than a legal footnote.