Ugh, this thread. OP, when using a downgrader and it errors out, just reboot and go back into homebrew and launch the downgrade again. It will complete the process and you'll be fully downgraded. Also, go with AuReiNand. It saves you from a lot of headaches. To install it, you just copy the files directly over to your SD. To unlink your NANDs, you go to system settings on SysNAND, go to format the system, and when the big, red button pops up, eject your SD card then format. Afterwards, you can put it back in. After doing this, run Emunand9 and create an EmuNAND.