ultrasn0w works great on my iphone 4 on 1.59.00 in Europe (on 4.0.1 with jailbreakme and now 4.1 with limera1n and preserved 1.59.00 baseband). But if I'm on an international train that goes around the country side, where there are big holes of not having service, sometimes the phone will get stuck in "no service" Airplane mode on and off won't help it or it'll sometimes get stuck on that 1 bar of signal without showing the service provider then it will say sim error if I flick airplane mode back and forth. AFAIK, it's happened on both 4.0.1 and 4.1. Otherwise, if I'm just in an area that has no service occasionally (not a drought of service), it works amazingly. And a reboot always fixes these problems. But, anyone else? Just curious Not the end of the world, and when I'm in the states, I don't need the unlock as I'm on AT&T but I still would like to know about it for clarification. Also, I didn't hactivate it. When I upgraded to 4.1, I had my AT&T sim in and it said phone activated and I could navigate around the home menu before I used limera1n to jailbreak and eventually ultrasn0w to unlock.