I've noticed that there are quite a few different ways of loading flashcarts on 3DS, and that theoretically if a cart appears on the 3DS menu it should be possible to boot it; what happens in my case, however, is that if I launch the flashcart I'm greeted by a white screen, and Google didn't help me find anyone who has had the same issue. I'm using a cart I bought around September 2011, so the firmware must be from around that time (its website is all but dead now). Here are some picture in case they might help. Also, I can upload the firmware, should it be of any use. EDIT - here's the last version of the website I could find.