Editing Swap Magic

Swap Magic is a specialized PlayStation 2 game disc used for tricking the console into reading non-retail or burned game discs, homebrew software, or games outside the console's region. The software has existed since at least mid-2003, with several different versions of the disc having been developed.

Swap Magic and its related mods, such as the Magic Switch and Swap Tool, which are used to allow the user to swap discs without the system being aware, are notable over other methods (such as a modchip) due to the fact that they do not void the PS2's warranty.
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The Swap Magic disc allows the user to boot into software which allows the system to read discs that it would normally refuse because of the lack of a burst cutting area on discs that have been burned with an ordinary DVD drive, as opposed to regular retail discs which are stamped or pressed en masse. The user then removes the disc (after installing small modifications to prevent the system from detecting the drive being opened) and replaces it with another disc which can then be started. The software also allows other homebrew software to be run from a memory card or USB flash drive.

Swap Magic and most other non-Sony-made PlayStation 2 bootable discs use a method of "growing" and "splicing" stampers from original PlayStation 2 discs, a method of growing a stamper from an original game disc and joining a new stamper with the program data on to it; in essence, the resulting discs contain a portion of an original disc.

Datel, the first company outside Sony to make a bootable PlayStation 2 disc, researched the protection and produced their own discs with protection in their on-site mastering facility. 

Source: https://en.wikipedia.org/wiki/Swap_Magic