Distributing or downloading Nintendo's proprietary BIOS, firmware, or decryption keys is generally considered under copyright law and the Digital Millennium Copyright Act (DMCA). Nintendo has historically taken aggressive legal action against sites hosting these files.
: Files used for system-level functions like the shared font, camera support, and the Mii data folder. How to Legally Obtain 3DS System Files Nintendo 3ds Bios File Download
When setting up 3DS emulators like Citra or Folium, you may encounter requests for a "Nintendo 3DS BIOS file" or "System Files." Unlike older consoles, 3DS emulators often don't require a single BIOS file to boot, but they do require specific and system data to run encrypted games or access system features like the Mii Maker. The Legality of BIOS and System Files How to Legally Obtain 3DS System Files When
To get these files safely, you must have a 3DS console with installed (typically via 3DS.guide). Distributing or downloading Nintendo's proprietary BIOS
: A database file required for games released after 2015 that use specific encryption "seeds".