Many "BIOS Download" sites are fronts for malware and viruses.
You will not gain better emulation performance. You will not unlock secret features. You will likely download malware, expose your personal data, or infringe on Nintendo’s copyright. Nintendo 3ds Bios File Download
These can be dumped into a seeddb.bin or aes_keys.txt file for use in emulators. 📁 Where to Place Files Many "BIOS Download" sites are fronts for malware
Whether you are seeing a specific (e.g., "AES keys missing")? Guide you on how to dump files from your own hardware? You will likely download malware, expose your personal
Every 3DS console has minor revisions in its boot ROM. Malicious actors rename viruses as boot9.bin to trick users. A file hash from a random site will never match your personal dump.
Finding a 3DS BIOS (or firmware) file can be a bit of a headache because of the legal "gray area" surrounding emulation. If you are looking to set up an emulator like Citra, What is the 3DS BIOS/Firmware?