That was the first way Wii owners got homebrew software running: the Wii version of Zelda: Twilight Princess didn't do a bounds check when reading the name of the player's horse from a save file.
Err, no, that came later. Much later. The original released homebrew was the Twilight Princess hack. There were a few others internal to the group first, but the attack you're referring to didn't happen until a good year, year and a half later.
http://events.ccc.de/congress/2008/Fahrplan/events/2799.en.h...