How to Downgrade Your iPhone 3GS Using a Cydia Saved SHSH [Mac]Posted by admin
These are instructions on how to enable a firmware downgrade on your iPhone using a Cydia stored SHSH and Mac.
In order for these instructions to work you must have previously jailbroken on an earlier firmware version and opened Cydia allowing it to save your SHSH on file. You can learn more about this situation here
Navigate to the Desktop, uncheck the If no extension is provided, use “.txt” box, and make sure the filename is just hosts with no extension. Then click the Save button.
Drag the hosts file from your Desktop to the /etc folder we still have open.
You are now ready to downgrade your device. Simply put the iPhone into DFU mode and in iTunes Option+Click the Restore button to select the firmware you would like to downgrade to. If you get error message 1011 or 1013 just ignore it. If you get error message 1015 repeat the entire restore then jailbreak after it fails the second time.