I had a JB'd iphone 4 on 4.01 and last night i restored a fresh 4.01 on my phone in anticipation of 4.3. Well, just now i update my phone to 4.3, and after it loaded on my phone itunes gave me error 1013. I told tiny umbrella to get me out of DFU and it did. my phone booted, but my signal only showed 1 bar. Which is impossible because i get -65dbm on average since i'm about 60 feet from a tower! It seemed to make calls ok, and internet speed seemed ok, but what the hell is going on? I just downgraded back to 4.01 again now. and everything seems ok. what should i do?