, are designed to function without an external BIOS file by emulating the system software
However, some open-source emulators like (official version) do not require a BIOS file — they emulate the 3DS hardware at a higher level. But forks like Citra MMJ or PabloMK7's Citra may request BIOS files for better compatibility or performance on Android. 3ds Emulator Bios File Download For Android
Does a BIOS file improve performance on Android? , are designed to function without an external
Always scan any downloaded file with VirusTotal, but better: don’t download BIOS files at all unless you dump them yourself. 3ds Emulator Bios File Download For Android