The Bios files are required if you want to play games on the 3DS emulator. Click here to learn more, read a step by step guide & Download the 3DS Bios files.
To play Nintendo 3DS games on your PC you need the emulator, and you need a 3DS BIOS, put the BIOS map inside the map with the emulator. And you will be able to open .3ds roms with the emulator.
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