I just transferred from my source 3ds to my target 3ds. The target 3ds now has the NNID on it, and 4 swords. I restored the source 3ds with a nand backup right before i system transferred. If i transfer my NNID back to my source 3ds, could I still use the target 3ds to perform an additional downgrade for another system? Or do I have to use whichever system the NNID is on?