For some reason, I cannot get the H&S app to load FBI after injecting it to sysnand. It just opens the app. I'm on 4.2U on emunand currently. Was previously on 9.2.
I don't know if this will help you, but I was having the same issue as you when I was trying to install FBI to my SysNAND. Boot up RxTools, and go to Advanced. Inject to SysNAND, then go to verify TMD to see which version you're running. Now, instead of injecting it with RxTools, power off and go to the fbi_injection folder that came with your RxTools download and use the fbi_inject.app and fbi_inject.tmd that came with the download, and put them on the root of your SD card. Boot up RxTools again, and this time, inject like normal and it should load up