Unlocking a phone is beneficial because of some reasons like: not voiding the warranty, not causing problems with software and also updating iOS. People try to unlock because the always want to use the phone in various locations for carrying different GSM carriers at different times. To unlock iPhone 4 one has to maintain or follow some several steps which are mandatory. These are:
Check for baseband- Go to settings, choose ‘About’ and then click on ‘Modern Firmware’. If you will see 1.59.00 than you have got the luckiest iPhone as you do not need any hardware modifications to unlock your phone. In other basebands, it may need to unlock the phone.
Disable iTunes- it is always better and safe to disable iTunes first and then go to next step.
Connect and Install- Next, you will must connect the phone to a PC and install any software that helps in breaking the iPhone lock. This program will be installed and ready to move. iTune access and change settings- Now you will open the settings of the iTunes program and change the ‘Auto’ update to ‘Never’. It is mandatory as well.
Remove SIM- You will keep your IP address with port 22 handy before doing this. Now you can remove the SIM from your device and then restart it.
Process completion- The phone will start and check for new configuration and program customizations. It will take a few minutes for the phone to remove the previously installed files and it would install the new processes.
Reboot- In the last step, you have to reboot your device, insert a SIM card and see whether you are able to make a call or receive a text message. If all these functions are being completed successfully, you will unlock iPhone 4 and can now use the mobile in various locations.