The hack exploits a [http://en.wikipedia.org/wiki/Stack_smashing buffer overflow error] caused by loading a specially crafted save file for Twilight Princess. The save file stores the name of the player's horse in the game (originally "Epona"). This save file presents a name much longer than expected to the Twilight Princess game, which causes the Wii system to crash when it tries to load the horse's name. With this crash, the system is made to run a loader program (which was loaded by the game as part of the name) instead of Twilight Princess's code which then proceeds to load a program from the Wii's front SD card slot. Any program that is placed on the root of the SD card, with the filename "boot.elf" or "boot.dol", will run.