I would recommend the following through my trial and error.
You should have done a normal backup not TWRP. If you have already done a titanium backup then just reset your phone to factory default. Go through above steps and male sure you re-root to be on the safe side. Make sure you are backing up the stock ROM to your SD Card and not your external SD Card. Make sure your ROM is on your external to throw on your stock slot. Back up wipe and flash
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