How To Update Your iPhone, iPad To iOS 5.1 Without Losing Your Data
Apple released the new version of iOS i.e., 5.1 earlier this month along with The New iPad. The new iOS 5.1 doesn't really bring any new feature but it contains patches for the vulnerabilities that were existing in the existing iOS 5.0.1. The new update basically patches the exploits used by the jailbreak community in developing the jailbreak. Having said that, you can now download and install the latest version of the iOS on your iPhone or iPad or iPod touch. We'll guide you through the entire process of updating iOS device and restoring through the backup so that you don't lose your data.
IMP : If you rely on ultrasn0w unlock and jailbreak, follow the tutorial posted here.
Follow the below steps to update your device to iOS 5.1
Step 1: Connect your iOS device to iTunes via the connection cable and launch iTunes.
Step 2: Wait for iTunes to show your device details then right click on your device name and select back up my iPhone option. iTunes will now backup your device contacts, recent call logs, messages, photos, application data, music and everything.
Step 3: Now from the help menu in the iTunes, select check for updates and iTunes will check for the updates and alert you that there is an update iOS 5.1 for your device and will ask you if you'd like to download and install it. Select Yes and the download will begin.
Step 4: Once the download is complete, iTunes will automatically start updating your device. Once done, your device will reboot and you'll be taken to the start up screen which should look like these:
Here, instead of selecting the option Set Up as new iPhone, select Restore from iTunes.
Feel free to post any comment in case you come across any errors while restoring.