Apple released their next-gen mobile operating system iOS 5 for public on October 12th, this iOS 5 update also brought in new baseband version 4.11.08 for iPhone 4 users. People who updated their iPhone 4 to iOS 5 unintentionally lost their unlocks (GEVEY SIM).  There’s still no unlock available for Baseband 4.11.08 but there’s a solution for that. As Apple is still signing their previous version of iOS, iOS 4.3.5 you can still downgrade your iPhone 4 to baseband 4.10.01 which is unlockable with Gevey SIM.

Follow our complete step-by-step below to downgrade your iPhone 4 to 4.10.01 baseband.

How To Downgrade Baseband 4.11.08 to 4.10.01 on iPhone 4:

Things you will be needing during this process: 

• A restore copy of iOS 4.3.5 which you can download below.
• iPhone 4 (GSM)
• iPhone 4 (CDMA)
• iTunes 10.4 which you can download below.
• Windows 32-bit (Direct Link)
• Windows 64-bit (Direct Link)
• Mac Os X (Direct Link)

Step 1: Download and install iTunes 10.4 or earlier. You will need to remove iTunes 10.5 first.

Step 2: Download iOS 4.3.5 IPSW for iPhone 4(Link given above)

Step 3: Put your device into DFU mode .

Enter DFU mode by following these steps:

• Hold Power and Home buttons for 10 seconds
• Now release the Power button but continue holding the Home button for 10 more seconds
• You device should now be in DFU mode

Step 4: Connect to iTunes and it will say that your device is in recovery mode and needs to be restored.

Step 5: Go ahead and click shift+restore (Windows) or option+restore (Mac). Select the IPSW you just downloaded.

Step 6:  iTunes will verify with Apple server and begins restoring your device. Once completed you will need the official SIM card to activate it. You can use TinyUmbrella to confirm that you now have baseband 4.10.01.

This is it you can now unlock your iPhone 4 running iOS 4.3.5 using Gevey SIM, if you want to to run iOS 5 on your iPhone 4 and unlock it with Gevey SIM follow our step by step guide posted over here to create a iOS 5 custom firmware IPSW file which will preserve your baseband to 4.10.01 which will allow you to unlock your iPhone 4 using Gevey SIM.

Let us know if you face any problem during this process, you can leave your comments below, on our Facebook page or on Twitter we will get back to you immediately.

We will keep you updated on this, stay tuned!

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