I just got a brand new 32gb Sandisk SD card from a trusted place and it works on my PC and on my phone with no problems. So I formatted it to Fat32 to use on my 3DS using Windows built in tools and copied all the files from the other SD over. But it just hangs on a black screen with the blue light on. The other SD card still works perfectly on the 3DS. I'm gonna try emunand9 to format it right now, but might as well make the question in case that doesn't work.