Gundam Wing Endless Duel

Select "Versus" or "Trial" mode. Highlight Tallgeese and press L x4, R x4, L, R, L, R, L, R, L, R at the character screen.

Press Down, Forward, Down, Forward, + Attack.

First highlights Wing Zero and press L, L, R, R, R, R, L, R, R, L, L, L, R. This will transformed your gundam into Wing Zero in Endless Waltz.