I have acquired an iPhone 4 from Canada and I cannot unlock it with my Gevey Ultra- and I don't know why. I know my Gevey is legit because its works in another iPhone 4 with IOS 4.3.3 perfectly. The only difference I can find between these 2 phones is the model and firmware. Canadian MC603C / 03.10.01 American MC610LL / 04.10.01 Would that make a difference? When I install the Gevey and power it on, it does nothing. No "accept" screen or anything. It just says "No Service".