i downgraded my 3ds using this guide here:
http://gbatemp.net/threads/tutorial-from-9-2-or-any-lower-firmware-to-cfw-4-5-without-gateway.378371/
But when I realizing there was nothing I could do, I wanted to restore my back up. However, for some reason I was downgraded to 4.2 instead of 4.5...