When FBI fails (e.g., the seed is unavailable from Nintendo), you must manually obtain the seed from a third-party database (like the "3DS SeedDB" project) and inject it.
If you still face errors (e.g., "SeedDB not found" or "Install failed") after placing the file: 3ds seeddb.bin
Which you are planning to use (Citra, Panda3DS, etc.)? When FBI fails (e