To dump your own BIOS and system files, you need a hacked or homebrew-enabled 3DS. Tools like GodMode9 are used to extract the bootrom and aes_keys from your personal console. You then transfer these files to your Android phone via USB or cloud storage.
If you have a Snapdragon phone, installing custom Adreno drivers can double your FPS in games like Pokémon Sun and Moon or Zelda: A Link Between Worlds . 3ds emulator bios file download for android better