Gamecube System (Gamecube) Cheats & Tips
Cheats, codes, tips, hacks, how to's, and walkthroughs
Unlock Alternate Starting Sound
Turn on the Gamecube and hold Z while the logo is forming.
Spin the Gamecube Logo
While the cube is bouncing down to form the "G", hold A.
Set the System Date and Time
While turning on the system, hold A. Alternatively, simply turn on the Gamecube with no disc inside.
While at the title screen, hold B + Y + Start (Note: This works with most games).