Let me know if you have any further questions!
: If you are using a frontend like ES-DE for Android , you typically place bios files in a specific /ROMs/bios/ folder. A Note on Public Downloads 3ds bios file download for android
Downloading copyrighted system files or games (ROMs) you do not own is illegal in many jurisdictions. Always refer to the Nintendo Support site for official information regarding their hardware and software rights. Let me know if you have any further questions