The Gamecube version of FIFA 2004 has two GBA link options: one that connects with the FIFA 2004 GBA version, and another that links with an empty GBA.
Connecting an empty GBA installs a pointless scoreboard on the GBA screen and unlocks 3 cheats in the Gamecube game.
By playing the GBA game, points earned in the handheld version can be uploaded to the Cube version which can then be spent to increase the stats of individual players or the entire team as a whole.
