iPhone 3GS Stuck in Recovery Mode Loop After iOS 4.3.5 Upgrade?

Hello Hendra, do you use Sn0wbreeze or PwnageTool to create a iOS 4.3.5 custom IPSW for your device? Or you have accidentally restored iOS 4.3.5 on your device? The thing is, since your device is running on iPad’s 6.15.00 baseband, you will not be able to restore a stock firmware on it. If you do, you will end up in endless recovery mode loop, just like what happened on your device. Anyway, to kick your iPhone 3GS on recovery mode loop you can use the standalone TinyUmbrella (Fix Recovery). You can follow the tutorial posted below on how to use TinyUmbrella (Fix Recovery).

Step 1: First, you will need to download TinyUmbrella (Fix Recovery) for your Mac or Windows.

Step 2: Download Zlib1.dll from here and put it in the same location where the downloaded fixrecovery43.exe is located.

Step 3: Then connect your iPhone 4 into the computer via USB cable and power OFF your device.

Step 4: Start iTunes as well as the downloaded TinyUmbrella (Fix Recovery) and put your iPhone into DFU mode.

• Press and hold the Power and Home button for 10 seconds.
• Then release Power button after 10 seconds but continue holding the Home button for another 10 seconds.

Step 5: That’s it! TinyUmbrella (Fix Recovery) will start fixing the error on your iPhone 3GS.

Anyway, I would recommend you to downgrade your iPhone 3GS back to iOS 4.3.3 as there is no untethered jailbreak support for iOS 4.3.5. To do that, you can download saved SHSH Blobs (if you have) with the help of TinyUmbrella. The tutorial on how to downgrade can be found here. If you don’t have saved your SHSH Blobs, you don’t have to worry because you can create your own signed iOS 4.3.3 using iFaith SHSH Blobs Dumper. You can check this blog post on how to create signed iOS 4.3.3 using iFaith. Then make sure that you will use Sn0wbreeze 2.7.1 or PwnageTool 4.3.3.1 to create custom firmware for your device.