Ensure the file extension is strictly .opk and not .opk.zip .
If this is the emulator version, you will need to provide your own game files: Create a folder named GB or Roms on your SD card. Place your .gb files there. Ensure the file extension is strictly
Open the Mac-2 app and navigate to this folder to select your game. Ensure the file extension is strictly
Most OPK emulators allow you to access the menu by pressing or the Reset button to change controls. Adding Games (ROMs) Ensure the file extension is strictly