At the title screen, simultaneously press L2,R2,X,O,Triangle,Square. If you entered the code correctly, you will hear a sound. Teams like Dream Team, Street Team, All of the Youth JR teams... will be availiable in VS mode and Competition mode. PS: All six buttons together!!!
At the title screen hold L1 & R1. Then press triangle & square at the same time. If you entered the code correctly you will hear a sound and "edit team" will appear in the title screen written (in Japanese). Now you can edit your own team and save it then play with it.
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