Downgrade


Note:

For iPhone 4 / 3GS, iPod Touch 3G and iPod Touch 2G (MC) you MUST have SHSH blobs of the older Firmware, if your SHSH Blobs are saved on saurik's server then follow this steps to get it on your computer.
Step 1: Connect your Device and Launch TinyUmbrella (Download below) then Check on "Advanced Options
Step 2: Now select your Device, Firmware and Location (Choose Cydia)
Step 3: Click on "Save My SHSH" button

Required:

- Download iOS 4 Original Firmware from Here.
- Download TinyUmbrella, latest version from Here.
- iTunes 9.2 for Mac and Windows from Here.

Steps:

Step 1: Put your iPhone in DFU Mode, guide posted here.
Step 2: This Step for iPhone 4 / 3GS, iPod Touch 3G and iPod Touch 2G (MC), If you are on iPhone 3G or iPod Touch 2G then skip this Step.
Run TinyUmbrella (download above), and Hit Display SHSH (If you have already saved SHSH on your computer, then just drag and drop it in TinyUmbrella)Now Hit on "Start TSS Server" buttonLocate "C:\Windows\System32\drivers\etc\" for Windows and "/etc/" directory for Mac, then locate