Glad it worked for you. Which method did you end up using, the RUU or the TWRP stock backup? Just out of curiosity, they are both valid methods. But the RUU is probably easier in your situation, and probably makes for a "cleaner" install (writes all partitions to "factory" condition).
The description "full stock" firmware to me implied "official" and "signed", but that isn't the case in reality. It's counterintuitive that a fully stock (unmodified) firmware would be missing the signature. But I'm sure there is a reason for it to be unsigned (don't know the background, personally).
It's not that silly. I made the same error a while back, thinking that sneakyghost's firmwares were signed. In my case, it flashed anyway since I was s-off, so I don't think I knew any better until someone told me.I feel so silly, considering I was using sneaky ghosts unsigned fullwipe firmware... Blah!
Again, you both are awesome, kind to a moron!
The description "full stock" firmware to me implied "official" and "signed", but that isn't the case in reality. It's counterintuitive that a fully stock (unmodified) firmware would be missing the signature. But I'm sure there is a reason for it to be unsigned (don't know the background, personally).