Game Boy Color system hardware Cheats - GameBoy Color

In-game reset
Press [A] + [B] + [Start] + [Select] during game play to reset most Game Boy and Game Boy Color games.

Invert colors
Press [Right] + [B] at the Game Boy logo to reverse the screen and sprite colors. This may make the game easier to see in dim light.

Other colors
Other color schemes (as stated in the manual) may be selected at the Game Boy logo by pressing the following combinations. Note: This only affects regular and not color Game Boy games.

Combination	Background	Color 1	Color 2
None	Green, Blue	Red	Red
Up	Brown	Brown	Brown
Up + A	Red	Green	Blue
Up + B	Dark Brown	Brown	Brown
Left	Blue	Green	Red
Left + A	Dark Blue	Red	Blue
Left + B	Green	Green	Green
Down	Yellow, Red, Blue	Yellow, Red, Blue	Yellow, Red, Blue
Down + A	Yellow, Red	Yellow, Red	Yellow, Red
Down + B	Yellow	Blue	Green
Right	Green, Red	Green, Red	Green, Red
Right + A	Green, Blue	Red	Red
Right + B	Invert	Invert	Invert