1 Backup and restore your iPhone through iTunes.
With your iPhone connected to the computer, open iTunes and click on your iPhone in the left-hand window pane. If your iPhone does not sync automatically, click "Sync" in the "Summary" tab to make a current backup.
Now that it is backed up, click "Restore" to wipe your iPhone clean and restore factory settings. While this step may not be necessary, it will prevent any installed applications or changed settings to interfere with the unlocking process.
2 Note the firmware version.
Once your iPhone is restored (this can take a long time, be patient), check your phone's firmware version by browsing to Settings>General>About>Version. Write down this number.
3 Insert SIM card into the iPhone.
The SIM (Subscriber Identity Module) card stores unique data about your account to identify your device on the mobile network. Once you have the SIM removed from your old phone, pop out the iPhone's spring-loaded SIM tray. Use the supplied tool or a bent paperclip to depress the button, located at the top of the phone in a recessed hole. Insert the SIM carefully into the tray (it only fits one way) and slide it back into the iPhone. An error message will pop up, ignore it.
Although you can unlock your iPhone without a SIM, it is recommended that the SIM stay in the entire unlocking process to prevent compatibility issues with your carrier.
4 Download and install three things: QuickPWN, firmware and boot loaders.
Browse to QuickPWN's home page and find the download section. Once there, download QuickPWN and the matching firmware version (from Step 2).
Use the link supplied to download the bootloaders.
Once you have these three things extracted and saved to a folder on your computer, you are ready to start the unlocking process.
5 Unlock your iPhone.
Run QuickPWN and follow the onscreen instructions. It will ask you to select your iPhone version and instruct you to locate the firmware and bootloaders. Be prepared to press a series of buttons in succession. If you mess up, don't worry, you can try again once the sequence is complete.
6 Finish the process.
Once QuickPWN has finished its magic, your phone will be unlocked and ready to make calls on your new carrier.
Topons hope it can help you. Thank you！