After seeing how people having problems with FBI injection, I decided to take a look into process to see what can possibly go wrong. Basically, there's two main issues with previous injection methods: the first problem I see is that H&S is an optional app and only gets updated through internet and not card game updates (so even if you running FW9.x there's still possibility your 3DS have old H&S app version). As of now there's 14 different revisions of H&S app and to make things done right...
[Release] 3DS FBI CIA Manager NAND Inject Generator (JPN/USA/EUR/CHN/KOR/TWN)
[Release] 3DS FBI CIA Manager NAND Inject Generator (JPN/USA/EUR/CHN/KOR/TWN)