Hi, Just want to confirm to you guys who have a factory unlocked iPhone 4. My iPhone 4 can be used on different carriers, however every time I change my sim I will get a no service even after rebooting my phone. The only way to use the new sim would be to connect my phone to itunes to go through the activation process, the activation will go through and the signal for new sim will start showing. The process is the same when using a different sim from the same carrier. Is this really normal? Is my iPhone 4 factory unlocked or not? or semi factory unlocked (if it exist) since I always need to connect to itunes and go through activation everytime I change my sim both on the same carrier and different carrier. Also, upon checking my IMEI on sites which tells whether the unit is sim locked or not shows that my unit is indeed sim locked, funny thing is I can use it with sim cards on different carriers provided I use iTunes to activate it.