How to Reset Game & Watch Systems to Factory Settings
Support | Game & Watch: Super Mario Bros.
In this article, you'll learn how to reset the Game & Watch: Super Mario Bros. and Game & Watch: The Legend of Zelda systems back to factory settings.
Important: Once this process is done, all save data will be deleted and cannot be recovered.
Complete these steps
Press and hold the following buttons for four seconds: PAUSE/SET Button, Up (on the +Control Pad), and the POWER Button.