USB Gecko is a cheat device for the Wii that allows for considerable modifications to Wii games. It works by loading a custom operating system onto the Wii, after which codes can be input for specific games. Contrary to popular belief, the use of USB Gecko is not completely identical in function in Brawl in comparison to Action Replay, due to Brawl's lack of a dedicated debug menu. Production of the device ended in 2010 for unknown reasons.
Initially a popular choice for users who wished to modify Brawl, advances in the hacking scene for the Wii and for Brawl have caused the device to become antiquated. The default OS loaded by USB Gecko, Gecko OS, was later made usable without the device, and it can potentially be loaded with the Smash Stack exploit or with The Homebrew Channel. A variety of alternatives are also available to Gecko OS, such as WiiLauncher. Outside of the console itself, Dolphin offers a variety of built-in hacking options for Brawl.