Suppose we...ok stay with me here. Suppose we first use the NUS downloader...hey, you staying with me here? We use the NUS downloader to first download an update. We then mod it somehow...but thats not the point, this is just a theory on how to install the mod. Ok. then we update while filtering and editing packets sent from the router to your ds with some random router tools. Swap out the files downloded from the nintendo servers with the modded ones on your computer. That is my theory. Of course, I haven't tried it yet, but a friend tried installing a normal update that way and it worked. I don't know if modded firmware installed the same way will work or not, because I thought the 3ds had good security.