You can't get a backup of the NAND before the downgrade without a hardmod. You just gotta check and double check and triple check that you are doing the right thing before pulling the trigger on something as dangerous as downgrading without a safety net.
I know and that's what I was referring too. Even if you can't do it yourself. Ask someone if they can do it for you. Don't proceed onto downgrading without a backup. There's multiple cases where members have completely bricked there console because of downgrading. That should tell most that this isn't safe to do without first making sure you have a nand backup.