How To Downgrade iOS 4.0.2 To iOS 4.0.1 iPhone 4, 3GS, 3G, iPod Touch 2G, 3G

Have you accidentally upgraded to iOS 4.0.2 the firmware upgrade that was released to fix the PDF exploit used by JailbreakMe 2.0 Star? Unfortunately you cannot jailbreak iOS 4.0.2 if you are an iPhone 4 user. Others check out our article on how to jailbreak iOS 4.0.2 on iPhone 3G, iPod Touch 2G with redsn0w 0.9.5b5-5 (Windows) and jailbreak iOS 4.0.2 iPhone 3GS with PwnageTool (Mac OSX).

For those of you who are looking to downgrade iOS 4.0.2 toiOS 4.0.1 or iOS 4, here is a step by step guide.  You can downgrade iPhone 4, 3GS, 3G, iPod Touch 2G, 3G from iOS 4.0.2 to iOS 4.0.1/ 4 / 3.1.3 /3.1.2, provided that you have earlier saved SHSH blobs (ECID SHSH) on Cydia server (via ‘make my life easier’ button) for the corresponding older firmware.

Downgrade iOS 4.0.2 To 4.0.1 With Saved SHSH Blobs

1. Download IPSW files for the older firmware (download links at bottom).

2. Put your iPhone into DFU mode.

Plug in your iPhone to your Computer and turn the device off. With iTunes running, hold down the Power and Home buttons for around 10 seconds. First release the Power button, still holding the Home button. Wait till your Computer shows up a new USB device.

3. iPhone 3G and iPod Touch 2G (non-MC), skip this step and go to step 4. This step is for iPhone 4, iPhone 3GS, iPod Touch 2G (MC model), 3G.

The trick is to make iTunes believe that it is contacting Apple server, while actually it talks to Saurik’s. This can be done by adding Saurik’s server IP to your system hosts file. This is the same way we can block web sites.

Mac OSX users, jump to this section.

Edit And Save Hosts File In Windows

Navigate to C:\Windows\System32\drivers\etc folder on your PC.

Open hosts file in Notepad and add the following line:

74.208.10.249 gs.apple.com

Note for Windows 7, Vista Users: You get a ‘Access denied’ error when you try to save the Hosts file in Notepad. A work around for this issue is given by Microsoft. The trick is to open Notepad using the ‘Run as administrator’ option. For doing this, search for ‘Notepad’ in the Start Menu search box. Right click on Notepad and then select ‘Run as administrator’.

Type your admin password when prompted by the UAC and click ‘Allow’ or ‘Yes’ for confirmation.

Edit And Save Hosts File In Mac OSX

Open Finder, and select ‘Go to Folder…’ from the Go menu.

Then enter /etc and hit the Go button. Find the hosts file, right click it and open it with TextEdit.

Add the following line at the end of the hosts file:

74.208.10.249 gs.apple.com

Then click Save As, and unselect the option ‘If no extension is provided, use .txt’ before pressing the Save button.

4. Restore your device to the older firmware you downloaded in the first step. For this, open iTunes, hold down SHIFT key (ALT in case of Mac OSX) and click on the Restore button in the left panel.

Browse and select the IPSW firmware to start the restoration process.

5. Let iTunes restore your iPhone to iOS 4.0.1 or older firmware. Once the installation is complete, iTunes may bring up errors 1015, 1013, or 1011. Once you see these error messages, it is confirmed that the firmware installation is complete. Don’t worry about them as there is a way to get rid of them.

6. Since iTunes is unable to complete the restoration, you need RecBoot to exit the recovery mode. Run this small tool and click ‘Exit Recovery Mode’.

That’s it. After your iPhone restarts, it will be on an older firmware. If it is on iOS 4.0.1 or iOS 4, you can jailbreak it using JailbreakMe 2.0 Star or Redsn0w 0.9.5b5-5 or PwnageTool and unlock it with Ultrasn0w.

Download iOS 4.0.1

Download iOS 4

Download iTunes 10

Download RecBoot

Not saved your SHSH blobs?

There has been some discussion going on around how to downgrade iOS 4.0.2 to 4.0.1 without SHSH blobs, with many users claiming that it didn’t work for them. Only some have found the method working, so we caution you to proceed with discretion.