iOS Downgrade Guide from Firmware 4.3.5 or 4.3.4 to Firmware 4.3.3 iPhone 4, 3GS, iPad, iPad 2, iPod Touch [UPDATED X3]

Apple Lossless Audio CODEC (ALAC), has released the update to the new firmware version iOS 4.3.4, fixing the previous vulnerability exploited by JailbreakMe.
An additional update, version 4.3.5, is available through iTunes.

In this article we will see how to make a degrade to reset the firmware to a version previous and therefore vulnerable to the exploit used for the jailbreak.

UPGRADE: new version available TinyUmbrella to downgrade firmware iOS 4.3.3 su iPad 2
UPDATE 2: added Recovery Repair to exit recovery mode
UPDATE 3: addition the new version of TinyUmbrella which firmware supports iOS 4.3.5. Added some advice in the “Conclusions” paragraph.

1 – Premesa

If you don't know what we are talking about, I refer you as always to the article Understanding Jailbreak, Activation and Unlocking.
The guide is valid for iPhone 4, 3GS, iPod Touch (3G y 4G), iPad, iPad 2 (only version Wi-Fi for now!).

The only way to revert to a previous firmware version is to have previously saved the SHSH Certificate corresponding to the firmware version you want to restore.

Therefore, you should have followed our Guide to Save SHSH iOS Certificates.

Methods to downgrade firmware depend on how you have done the rescue in the guide reported above (via Cydia o TinyUmbrella)

2 - Download

Download to your computer, the firmware iOS 4.3.3 for your device.

• iPhone 4
• iPad
• iPad 2 3G
• 2 iPad Wi-Fi
• iPod Touch 3G
• iPod Touch 4G

3 – modo DFU

The device must be turned on. DFU mode.

1. Hold down the button Boost (the one above) pressed to seconds 3 and continue holding it during step 2.
2. without release the button Boost, Press the button Home (the one in the center), continuing to press it for 10 seconds.
3. Release the button Boost, continuing to hold the button Home for 10 seconds i.

If you have problems with DFU mode watch the video with explanations in Spanish:

4 – Restore via Cydia

If you have allowed Cydia to save the certificate remotely, the method to restore it is to edit the file hosts contacting saurik (Cydia author) server instead of server Apple Lossless Audio CODEC (ALAC),.

Window procedure

The path of the file to edit is:

C:WindowsSystem32driversetc

You will find the hosts file in that directory. Open it with Memo pad run with administrator permissions (only Windows 7 o Vista). Add the line to the end of the file:

74.208.105.171 gs.apple.com

Connect the device to the computer via USB cable and start iTunes. Press and hold the button BASIC and click RESTART. At this point you can select the firmware file you want to restore.

At the end of recovery, you may encounter error 1013 (or 1011, 1015) with iTunes. Ignore it and read the point”Exit recovery mode”at the end of the guide.

Edit the file again hosts, removing the line you added.

Procedure for MacOS

Su MacOS, the path to the file hosts is

/ Etc

Click on Finder, press the keys BASIC+APPLE+G write / Etc and click Go to enter the directory.

Copy the file hosts en Desktop computer and open it with TextEdit. Enter your administrator password if necessary.

insert this line at the end of the file:

74.208.105.171 gs.apple.com

Copy the file to / Etc

Connect the device to the computer via USB cable and start iTunes. Press and hold the button OTHER and select RESTART. You can choose the firmware you downloaded earlier. The procedure to restore the firmware will start.

If you find the error 1013 (1011, 1015) with iTunes and the device remains stuck in mode recuperación, read the last point “Exit recovery mode".

Edit the file again hosts, removing the line you inserted.

4 – Recovery with TinyUmbrella (alternative)

If you have used TinyUmbrella, you have SHSH certificates saved locally on your computer. The recovery procedure is simple and fast.
Connect your iPhone, iPod Touch, or iPad to your computer and launch the program.

Click on Start the TSS server.

If it booted successfully, you should see a screen like this:

At this point, start iTunes, hold down the key BASIC (Windows) or OTHER (MacOS) and click on it Restore. Selecting the firmware file you want to insert into the device, the restore procedure will start.

If you find any errors, please ignore them and continue reading the next point.

5 – Exit recovery mode

If your device got stuck Recovery mode (recognizable by the screen with the cable and the iTunes icon), download TinyUmbrella:

Descargar TinyUmbrella 5.10.06 (Windows)

Descargar TinyUmbrella 5.10.06 (MacOS)

Connect theiPhone, iPod Touch o iPad and click the button "Exit recovery".

If it doesn't work with TinyUmbrella, Try it Recovery Repair (from the same author), always with the device connected via USB:

Descargar FixRecovery Windows
Descargar FixRecovery MacOS

NOTE: : The device must be turned on DFU mode (read point 3!).

6. CONCLUSIONS

once restored the firmware, you can continue again with jailbreak.

Click Jailbreak Guide 4.3.3 for iPhone 4, 3GS, iPad, iPad 2, iPod Touch if you want to continue with the jailbreak very quickly with JailbreakMe.

If you cannot restore due to 10xx errors, use the TinyUmbrella method directly by pressing the Start TSS button and using iTunes to restore as explained in point 4, "Restore with TinyUmbrella".