A simple and easy tutorial to restoring your NAND backup.
This restoration method assumes that you have access to gateways latest "Ultra" menu.
1.) Make sure you have your NAND.BIN is placed on your 3DS's SD.
2.) Launch the GW menu (the one where it has NAND backup, etc)
3.) Hold up while pressing "Downgrade" and you should be asked to restore the NAND backup to sysNAND.
Easy as 123! If you were reading GW's "News" posts, you would've most likely already been aware of this.
The purpose of this is mainly for the newcomers of Gateway who are running the 9.x firmware. Since gateway offers the ability to downgrade the system to 4.5 - if a user wanted to restore their system back to original/stock condition, before gateway was installed - then this tutorial would be ideal. I personally have had to restore my NAND using this method, quite a few times - mainly because I wanted to use CFW and install DevMenu, but my system kept failing on the DevMenu CIA installation process (it wouldn't connect to WiFi) and so I gave up and wanted to return to stock.