Hey guys! I bought my iPhone 4 about two weeks ago, it had 4.0.1 jailbroken firmware with ultrasn0w carrier unlock. I used the phone for some time (about a week), but when I tried to use my 3G internet it was saying something like "can't activate network". I gave the iPhone to a friend of mine and he updated it to 4.1. At first, everthing was fine, calls, sms, 3G internet... But after a couple of days of using the phone I noticed that it sometimes completly loses signal (goes to Searching...), nope, it's not "death grip", I use bumper. After phone restart everhing goes fine, I have full signal. Sometimes it loses signal when it's just laying on the table, it's very annoying. Microsim is originial, not hand-made. Is there anything I can do about it? Sorry for bad English, I'm from Russia. Thanks for help.