>If you have seen a performance deterioration and want to downgrade your iPhone 3G to the previous version then this this tutorial lwill take you through the step-by-step process to downgrade from iOS 4 to iPhone OS 3.1.3
Step 1: Download iPhone OS 3.1.3
click here to download
Save a copy of this iOS firmware on your computer desktop
Step 2 : Download RecBoot
Download this tool by click here and save it to your computer desktop.
Step 3 : Set iPhone To DFU Mode
(a) Plug your iPhone to the computer
(b) Switch OFF the iPhone by pressing the Sleep/Wake button. Swipe across the ‘Slide to Power Off‘ option to turn your iPhone off
(c) press the power button for 2 second (apple logo appears), press and hold the iPhone Home button for ten seconds (screen goes black).
(d) You can now release the Sleep/Wake button while the Home button is kept in the pressed state (till pc sounds for hardware connection).
(e) now relese the home button.
Step 4: Restore iPhone 3G using iPhone OS 3.1.3 firmware
open itunes and select shift+restore and let the process run.
iTunes might throw 1011, 1013 or 1015 error as seen below. You don’t have to panic. It’s normal, just ignore this error as the firmware has been successfully installed on your iPhone 3G. You need to use RecBoot utility to exit out of recovery mode.
You may require .NET 4.0 firmware for the application (
to work.Click here to download Microsoft .NET 4 firmware.
Thats it you are now on ios 3.1.3 that runs as smooth as silk ………
for any problem contact through comments………..