GBAccelerator GB Operating Instructions
When you first power on your Game Boy, it will be running at normal speed. At any time during gameplay you may change the clock speed by holding the Select button and tapping the A button. The GBAccelerator will cycle through the following speeds:
Fast -> Ultra -> Slow-Motion -> Normal
The power LED will indicate which speed is currently selected.
The following table shows the available speeds and their corresponding LED codes:
Disable Ultra Speed
If your system or game has trouble running at Ultra speed (or you do!), you can disable it. Hold down the Select and A buttons for approximately 6 seconds. The LED will flash 3 times to indicate that Ultra has been disabled. You can release the buttons at this point. Repeating the procedure will re-enable Ultra speed. GBAccelerator remembers this setting even after the handheld has been turned off.