Note : If you want to run the iOS 5 firmware, we recommend you to save your SHSH blobs on the iOS 4.3.3 firmware . If you encounter any error you will be able to downgrade your iPhone back to iOS 4.3.3. Also, this will only work on the iPhone.
Install iOS 5 Without Developer Account, UDID [How To] :
Stage One : Upgrade to the iOS 5 firmware
1) Download the iOS 5 IPSW file for your iPhone
2) Now launch iTunes and update your iPhone using iTunes. To do this, connect your iPhone to your computer, click on the Check for Update button with the Option (Mac) or Shift (PC) key pressed. Select the iOS 5 IPSW file from the place you downloaded it to.
3) Wait until it upgrades. A new activation screen will appear.
Stage Two : Backdoor activation exploit.
1) Triple click the home button. This will activate the Voice Over.
2) Triple click the home button and Emergency Call will appear.
3) Click on Emergency Call and, while it’s switching, swipe with your three fingers down.
4) The Notification Center will appear.
5) Click on the Weather widget. The Weather app will load.
6) Click on the home button to exit to the iPhone’s springboard.