Back Up Your Current iOS
Back up is always the first option whenever you have to upgrade. You can back up your iOS 4 or iOS 5 beta version using iTunes. All you need to do is sync your device with iTunes and a back up will be made automatically. Alternatively, you can right click on your device and click Backup in the iTunes Sidebar.
Upgrade to iOS 5
Now you need to download iTunes 10.5 Beta 7 or higher. Download it for:
Also download iCloud Control Panel.
Now you can download iOS 5 software for different devices listed below:
- iPhone 4 (GSM)
- iPhone 4 (CDMA)
- iPone 3GS
- iPAd 2 (Wi-fi)
- iPad 2 (Wi-Fi + 3G GSM)
- iPad 2 (Wi-Fi + 3G CDMA)
- iPad 1 (All)
- iPod touch (3G)
- iPod touch (4G)
Now, plug your device in and load up iTunes where you must go to the main settings and find the button Restore. Hold down Options for MAC and Shift for Windows and click on Restore. You will now be asked for the software to be installed. Head over to the folder where you have downloaded the OS from any one of the above links and select the IPSW file for installation.
Your phone will restart and iOS 5 will be installed on your device