How to Downgrade to IOS 4?

[emaildothales]

Anybody can help me to downgrade to IOS4?

The new IOS 5 made my hongkong iphone's MAPS be in Chinese even in USA.

I can't survive in China without an english map.

So please, help me!
rgs,
Thales

 

[alexreich]

You need to download the iOS 4.3.5 ipsw (iOS restore file) for your particular phone and put it on your Desktop, then try to restore to it in iTunes.

Steps to Restore:
1. Plug in iPhone.
2. Open iTunes if not already open.
3. Click your iPhone on the left hand side of the iTunes window.
4. alt+click Restore (or Shift+Click for Windows)
5. Find the firmware file you downloaded (it should be on your Desktop) and select it.
6. The iPhone should start to restore, if Apple is still signing 4.3.5. If they are not signing it, your restore will fail.

You may have already missed the 4.3.5 signing window, but if you really think that downgrading will fix your problem (I don't think so), you can try.

Apple was still signing 4.3.5 last night.

 

[christopherpm]

I'm trying this option, but after extracting and verifying the ipsw file, iTunes just sits at "Preparing iPhone for restore" for ages before showing error:-

The iPhone "iPhone" could not be restored. An unknown error occurred (1604).

 

[Wozza2010]

Your stuck

I wanted to downgrade to ios3 when ios4 had a super slow wifi bug for my iPad. Bottom line I couldn't do it so I was stuck with super slow wifi until they rolled out an update some 4 months later.

 

[flatlined]

To downgrade you need your SHSH Blobs from whatever iOS you want to downgrade to.

Has anyone downgraded from iOS 5 to another iOS with this method? http://www.iclarified.com/entry/index.php?enid=16512