Thanks for writing that up, already got to step 14 on my own, but the hack tool triggered my virus scanner so I got stuck there. After seeing how you did it and that it's safe, I kept going and it worked out.
1 problem though; while I was installing the .cia file, about halfway through FBI froze and 15 minutes later I restarted my 3ds. To my surprise the game seemed to be installed and it runs fine. Is it possible that I have an incomplete installation and that it'll crash at some point? Or does it starting up and working already mean that it's installed correctly?