Are you running into a when trying to launch a game?
The emulator could be designed to automatically detect and load the appropriate BIOS for the game being played. This would involve a database or a directory where users can place their BIOS files, which the emulator then references.
However, for full compatibility and advanced features, you may need specific system files:
If you own a 3DS game collection and want to play it on your Android phone, you need a dedicated 3DS emulator. Here are the top choices.