A game backup device, formerly usually called a copier and more recently a flash cartridge, is a device for backing up ROM information from a video game cartridge to a computer file called a ROM image and playing them back on the real hardware. Recently flash cartridges, especially on the Game Boy Advance and Nintendo DS platforms, only support the latter function; they cannot be used for backing up ROM data. Game backup devices also make it possible to develop homebrew software on video game systems. Game backup devices differ from modchips in that modchips are used in conjunction with systems that use generally available media such as CDs and DVDs, whereas game backup devices are used with systems that use cartridges.
Video game companies consider these devices as a tool for reverse engineering to circumvent copying. Most of the devices are made in China, but they are available globally. Recently, action has been taken by companies such as Nintendo to remove these devices from the marketplace, but the easy dissemination of information and selling of products over the Internet has made it difficult to eradicate this problem. Hobbyists argue that these devices are and should stay legal because they fulfill the need to back up games in case the original is damaged or lost; and because they permit the private development of new software on the device.
In Japan these devices are known as magicom (マジコン, "magic computer"), an umbrella term for any device that enables piracy on game consoles.
The spiritual forefather of copier devices can be traced back to the Famicom Disk System, an official add-on device for the Japanese version of the Nintendo Entertainment System. Users quickly discovered ways to copy these disks with ordinary home computers of the time and transmit the copied data to others using the emerging electronic bulletin board systems. Nintendo attempted to counter the piracy problem by slightly modifying the hardware in newer revisions, but they were unable to stop the unauthorized copying. Later, the Famicom Disk System was discontinued, supposedly because cartridge technology had caught up in capacity, but the influence of rampant piracy cannot be discounted.