SSX On Tour: Singlescreen Multiplayer Test
This is by me and @BrocoliMan2002. He helped me go through the code and he disabled P2's screen and stretched P1's screen from 320 to 640 to cover not just half but the full screen.
2P Mode Fullscreen 1.0
C20F9858 00000003
3C004420 90090010
38000000 90090020
82890000 00000000