Complete Guide to Downgrade iOS 4.0.2 to 4.0.1

This guide will explain how to return from the 4.0.2 firmware to 4.0.1 (useful for those who want to keep the jailbreak the device and has already updated).

The guide is only for iPhone 4 and iPhone 3GS for which has already been saved ecides using firmware via Cydia or Umbrella. Only with the ecides saved, it is possible to adequately perform the downgrade.

WINDOWS

Go to Start, All Programs, Accessories and click Notepad with the right button, then select “Open as Administrator”. Now go to C: / Windows / system32 / drivers / etc and open the hosts file, adding the end of this line:

74.208.10.249 gs.apple.com

MAC

By click on Go To Folders Finder menu “Go” and write / etc, and then click Go Select the hosts file and open it with Text Edit, then finally add the string:

74.208.10.249 gs.apple.com

Save the file.

Steps

1) you can put the iPhone in DFU (Connect your device to your computer and put it in DFU mode. To do this you must turn off the iPhone, simultaneously press the Home button and power button for 10 seconds, release the power button while continuing Home to press until computer detects the device. The iTunes logo with USB cable will appear do not set the device in Recovery Mode and DFU but will have to repeat the operation).

2) Once the iPhone is in DFU mode and will be detected by iTunes, click “Ok” and then select the 4.0.1 firmware (link) to restore the iPhone software. To do this you must press and hold down the ALT key (Mac) and Shift (Windows) then click on the Restore item. The restore operation requires 10 to 15 minutes.

After the process you’ll have your iPhone with firmware 4.0.1 running.