How to upgrade an unlocked iphone 4?

You can upgrade an unlocked iphone4 with new os version. There are few steps you have to follow to get this.

Step: Backup old jail break applications

You can use itunes to back up old apps(Cydia apps). Jailbreak the phone and install Apt backup from Cydia and click on Reset button. Now you are capable to get your all jailbreak apps reverse. You can sync itunes by appsync installation.

Step: Advance firmware via itunes

Use itunes to advance your firmware, you can do this either manually or automatically.

Step: Jailbreak it once more

To upgrade your jail broken iphone4, you can employ Pwnagetool for Mac while redsnow for Windows. You can use snowbreeze for both Mac and Window either.

You can visit this link for any difficulty or confusion: http://iphone4jailbreak

I hope now you can easily do this.

Best of luck!