Something weird happened. My PC was shut down for hours and so was my 3DS. I wanted to have a quick game before going to sleep so I turned it on, tried going online but hung on a connection screen, closed the lid and opened it only to get a black screen just like it happens while using NTR Viewer; problem is my PC was completely shut down. Another 3DS reboot and eventually I could go online, but it really seemed as for a while it fucked up my 3DS, even though there was no connection between it and NTR Viewer.