If you have upgraded your iPhone 4 or iPhone 3GS to latest firmware iOS 4.0.2, and you are not satisfied with its performance or you want to jailbreak your iDevice again as iOS 4.0.2 Jailbreak is not available yet you can easily downgrade it to iOS 4.0.1 without having your SHSH blobs saved.
Today I found something that the iPhone Devs told me “impossible”. I also spoke with iH8Snow, telling me that this sounds impossible. He also mentioned to me and one of my beta testers that this is possible if you allowed Cydia to store your SHSH/Blobs since Cydia will cache your firmware along the way.
Well, I’m pretty sure I proved them wrong.
So the story is that I have possession of clean (never before jailbroken) iDevices, and I managed to downgrade one of them and upgrade one of them to iOS 4.0.
Here is a step by step guide of how to downgrade your iPhone 4 or iPhone 3GS from iOS 4.0.2 to iOS 4.0.1without having your SHSH blobs saved.
1. Download iOS 4.0.1 by clicking HERE
2. After downloading the file rename the firmware file from .ipsw with .zip and extract that file on your desktop.
3. Open the buildmanifest.plist file in notepad and if you are using Mac then open it with Text Wrangler.
4. Search for the 8A306 and replace all such files with 8A400 and save it.
5. Now open restore.plist file and repeat the same procedure (8A306-8A400).
6. Now download iOS 4.0.2 by clicking HERE and open the .ipsw file with winzip or winrar, open it directly don’t extract it, open it and leave it open. You must use this exact file and don’t create a new file. If you have to create a file for reasons like you are on OS X, then use zip command line not explorer or finder to make the zip. I will assume you are using the original file opened in WinRAR for the rest of this guide.
7. Now drag all the file from iOS 4.0.1 to iOS 4.0.2 zip archive that you have left open.
8. Search all .dmg files having 002 at the end and leave only 001 files.
9. Save the archive and rename it back to orignal .ipsw.
10. Optional (This helps you to ensure that you get an SHSH file request for the future, but should not be necessary to just restore iOS 4.0.1). Add the 74.208.10.249 gs.apple.com line to the host file.
11. Put the device into DFU mode, watch the video on how to put your iPhone on DFU mode.
12. Now run iTunes and restore the firmware you changed.
Note: This method is only use to downgrade 4.0.2 to 4.0.1 due to the similarities in 4.0.2 to 4.0.1 and 4.0. This will not be a way to downgrade to 3.1.x to downgrade 3.1.x visit the link below;
Downgrade your iPhone 3G[S] from iOS 4 to iOS 3.1.3
{ 2 trackbacks }