This has happened to me before (twice). I have a jailbroken iPhone 2G v2.2. I accidentally updated Cydia the first two times, causing it not to detect my phone service anymore and making me unlock it again. However, this time, I didn't touch Cydia. I was just using the WiFi like always. Suddenly, it said the phone could not make or receive calls anymore. I restarted my iPhone, but this time, it wouldn't even let me access anything, it just told me to connect to iTunes. What should I do? Please help!!!