The following guide will allow iPhone 3G, iPhone 3GS and iPod Touch 2G (MC & non-MC), 3G users to downgrade their device firmware from iOS 4.1 beta 1 to iPhone OS 3.1.3 or iPhone OS 3.1.2. The same guide can be used to downgrade these devices from iOS 4.0 / 4.0.1 to iPhone OS 3.1.3 / 3.1.2. Unlike iOS 4.1 to 4.0 / 4.0.1 downgrade, iPhone 3G and iPod Touch 2G (non-MC) users don't require SHSH blobs saved for iPhone OS 3.1.3 or 3.1.2 for successful downgrade.
NOTE: If you have upgraded your iPhone to iOS 4.1 beta 2 then you might not be able to unlock it using Ultrasn0w 0.93 due to baseband upgradation. Moreover all iPhone 3GS and iPod Touch 3G users need to have SHSH blobs saved for iPhone OS 3.1.3 or 3.1.2 to downgrade from iOS 4.1 beta 1 successfully.
Downgrade iOS 4.1 to iPhone OS 3.1.3 / 3.1.2 on Windows & Mac
*Find all required download links at the end of post
- *If you want to downgrade your device from iOS 4.1 to iPhone OS 3.1.3 then download the iPhone OS 3.1.3 IPSW file respective to your device. If you want to downgrade your device from iOS 4.1 to iPhone OS 3.1.2 then download iPhone OS 3.1.2 IPSW file. After downloading the firmware file, place it on your desktop.
- Put your iPhone in DFU mode. Follow the steps below to put your iPhone into DFU mode:
- Start iTunes. Connect your device to your PC / Mac with the USB cable.
- Turn of your device completely.
- Now hold down the Home and Power button for exactly 10 seconds and after that release the Power button but keep holding the Home button until iTunes detect your iPhone / iPod Touch in recovery mode. Your iPhone or iPod's screen should be totally blank at this point.
NOTE: iPhone 3G and iPod Touch 2G (non-MC) users can skip the 3rd step and jump to 4th step. iPhone 3GS, iPod Touch 2G (MC models) and iPod Touch 3G users should proceed to step 3.
For Windows Users:
- Navigate to Start->All Programs->Accessories and then right click on the Notepad icon and choose Run as Administrator
- Now go to File menu in opened Notepad and choose Open or simply press Ctrl+O. Browse to C:\Windows\System32\drivers\etc and open HOSTS file.
- Once HOSTS file is opened, copy-paste the following line at the end of file as shown in the screenshot below
- Now again go to File menu and choose Save or press Ctrl+S.
For Mac Users:
- Click Go->Go to Folder and then enter path /etc
- Now open HOSTS file with TextEdit and add the following line with at the end of the file as shown in the screenshot below.
- Now go to File and choose Save As, uncheck If no extension is provide, use .txt and save the HOSTS file on your desktop.
- Now replace the original HOSTS file with the one you just saved on your desktop. Incase you are prompted for the password, just enter it and click OK.
TIP: If iTunes throw error 1015 during the restore process, use the instructions here to fix the error.
Once you have downgraded to iPhone OS 3.1.3 or iPhone OS 3.1.2, use the following tutorials to jailbreak and unlock your device:
For iPhone OS 3.1.3:
Jailbreaking iPhone 2G, 3G & iPod Touch 2G(non-MC models) with Redsn0w 0.9.4
Jailbreak iPhone and iPod Touch 3.1.3 with PwnageTool 3.1.5
Download Sn0wbreeze v1.5.2 to Jailbreak iPhone 3.1.3
Unlock iPhone OS 3.1.3 or iPhone OS 3.1.3 with Ultrasn0w 0.93.