If you need to unlock your iPhone 4 with the IMEI by iTunes, we can do this no problem; all iPhone mobiles are unlocked by code. After introducing the code the mobile will be unlocked, without losing its warranty or any data. These unlock codes are calculated in minutes, and you will instantly have your phone unlocked forever!
1. Insert a SIM card from a network other than the original network and dial the PIN
2. Note that there is no signal.
3. Install and run iTunes on your computer and plug in the iPhone.
4. iTunes will connect to Apple servers and unlock your iPhone in seconds (you might need to need to plug and unplug the iPhone twice)
5. Unplug and restart your iPhone and it will be unlocked forever.
If iTunes displays a note stating, "The SIM card inserted in this iPhone does not appear to be supported", your phone has not been unlocked. If this happens you must upgrade your iPhone to the latest version with a original network SIM inserted, and then restart the terminal and repeat the process from step 1.
Note: This unlock does not work if the iPhone is jailbroken and hacked with Cydia; you will have to upgrade or restore your iPhone to the latest version with iTunes, and then unlock it. Once unlocked you can re-jailbreak your iPhone.