This was a while back, but I have tried it since with the same result. I installed DLC for swapdoodle using Fbi, all seemed to be well, but the next day it disappeared. I looked for answers, and some people said that opening the eshop caused it to disappear, so I tried not opening it and it didn't disappear, so I thought everything was fine. I left the 3ds sitting overnight, and when I next checked, it was gone. I don't mind reinstalling it, but that can get to be a hassle. Does anyone else have this problem? Should I try to install it directly with godmode9?