Nintendo DMG-01 - Game Boy Console Manual page 126

4.5. Commands
Writing style ( 0 = Left -> right, 1 = up ->
down)
$06 - %vvxxyyzz data
vv = pal for dataset 1
xx = pal for dataset 2
yy = pal for dataset 3
zz = pal for dataset 4
$07 - %vvxxyyzz data
etc...
6. Sound On/Off ($08)
7. Transfer Sound PRG/DATA ($09)
This transfers your score (in .GAK format) data.
Set SGB Palette Indirect ($0a)
Page 126
TM
Game Boy CPU Manual
V 1.01