Even though I am using a 3ds, I think this is the best place to ask this question. So I myself have an original-size 3ds, and my boyfriend has a 3ds XL. I have a flashcart that says 'R4i 3DS Revolution for DS' on it. There's so many of these R4 cards and I'm not sure if there's even a hardware difference. I use Wood as the shell or interface for the card. First I used it on my 3ds, and it worked fine, then he used it on his system and it worked fine. Now when I try to use it on my system it doesn't work. I get an error message telling me to power down the system. So I tried his SD card, my two SD cards, nothing works on my system. The sad thing is I thought maybe I needed to reformat the SD card. And instead I actually formatted the system memory (!) without realizing what I was doing, and hence lost all of my Mii data and progress. Why doesn't the flashcart work on my system anymore?