No need to do any of the restoring if you have something like ifile installed.
If you do then simply follow this.
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If you don't have ifile or mobile terminal then you will either have to restore or re jailbreak.
But to make a valid note before you do any of that download iFaith and grab you SHSH blobs just incase you have not got them backed up so you can at least return to that iOS.
It's always handy to have ifile and mobile terminal installed no matter what. Even if you will never use them it's a great safety feature should you do something stupid.