Previously we shared a way to downgrade your iPhone OS 4.0 to iPhone OS 3.1.3 but this guide is to downgrade your iPhone OS 4.0 to iPhone OS 3.1.2 or lower. The only difference is that while reverting back from OS 4.0 to 3.1.3, we used the recovery mode of iPhone to simply restore our previous firmware. However inorder to downgrade your from OS 4.0 to OS 3.1.2 or below, you must use the DFU mode. The following guide will help you to downgrade your iPhone OS 4.0 to OS 3.1.2 or lower but your baseband (05.13.03) will remain unaffected.
Don't use this guide to downgrade from 4.0 to 3.0.1 as Saurik Server do not have any signatures for firmware 3.0.1. If you have saved your SHSH to Cydia Server, then follow the guide below.
Steps To Downgrade iPhone OS 4.0 To iPhone OS 3.1.2 or Lower
- First step is to add Sauriks Server address to your computer's HOSTS file. To edit HOSTS file in Windows and Mac, follow the guide here.
- Once done with editing HOSTS file, connect your iPhone to your PC or Mac.
- Turn of your iPhone completely and hold down home and power button for 10 seconds.
- After 10 seconds, release the power button but keep pressing the home button until your PC produces a beep sound or you see the following message on your computer screen
- Click OK. Now hold Option key while clicking Restore in iTunes and browse the 3.1.2 firmware for your iPhone 2G, 3G. You can download 3.1.2 custom IPSW file from here OR here. Restore process will take around 10 to 15 minutes.
Incase your encounter error messages with code 1011, 1013 or 1015, simply ignore these but if you encounter error messages with code 1601, 1602 or 1600, then try putting your iPhone in DFU mode again. You can look for a fix here.
Update1: Downgrade iPhone Firmware 4.0 Beta To Firmware 3.1.3
Update2: Downgrade Firmware 4.0 Beta To Firmware 3.1.3 On Mac
Update3: Downgrade iPhone Firmware 4.0 Beta To Firmware 3.1.3 On Windows
Update4: Downgrade iOS 4.0 to iPhone OS 3.1.3 | Windows & Mac
You can go through our step-wise tutorials on jailbreaking iPhone 2G/3G/3GS and iPhone Touch 1G/2G on firmware 3.1.3 using redsn0w 0.9.4, sn0wbreeze, PwnageTool 3.1.5. Unlocking can be done using ultrasn0w or blacksn0w.Contact Us for News Tips, Corrections and Feedback