If you accidentally updated your Jailbroken iPhone 3G or 3GS with an updated iPad 16.15.00 on iTunes, I’m 100% positive that you have just rendered your phone unusable because it’s now stuck on recovery mode.
I had this experience just a couple of days ago when a friend asked me to unlock her iPhone 3G with 4.2.1 iOS. I accidentally clicked the “Erase and Clear All Settings” and just rendered the phone unusable. (“Update” and the “Erase and Clear All Settings” will put your phone on recovery mode if it’s jailbroken and its baseband upgraded to 16.15.00)
And you probably know by now that with an upgraded baseband, you just can’t go back to the previous baseband version and downgrade your iOS to successfully recover your phone.
With your warranty gone because of the jailbreak and the baseband upgrade, you can’t ask Apple to fix or replace the device for you.
So, here’s what I did to recover the iPhone.
What you need:
i-REB-r4 | Download [here]
Latest iTunes version
1. Plug your iPhone to your computer while on “Recovery Mode” (look at the image above)
When you do this, your computer will detect the device and will ask you to recover it. Don’t do it, it will not work. Just close the pop up window and close iTunes.)
2. Run iREB-r4 and put your phone in DFU mode.
DFU mode or Device Firmware Upgrade is a special mode in the device that bypasses the loading of the operating system for recovery purposes; in this mode, the screen of the device is blank.
Click here if you want the step-by-step process on how to put your iPhone on DFU Mode.
3. Select iPhone 3G or iPhone 3GS.
This software will install some programs on your device that will fix the iTunes errors during the Custom iOS 4.2.1 Firmware restore in the Sn0wbreeze, Redsn0w and PwnageTool. Many users have had difficulty while restoring the Custom firmware on their devices using Sn0wbreeze, Redsn0w and PwnageTool. Hopefully iREB 4 will fix all of those annoying iTunes errors from now on.
4. After putting your iPhone 3G and 3GS in DFU mode, run iTunes and wait for it to detect your device.
Remember: When in DFU mode, your iPhone will appear as if its off and the screen completely blank. If your device displays the apple logo or the connect to iTunes logo, it means that you have to perform “Step 2” again until you get it right.
5. When iTunes detects your device, close the pop-up message, and press SHIFT+Restore and direct it to iOS 4.2.1 custom firmware you just downloaded.
iTunes will now restore your jailbroken iPhone 3G or 3GS with an upgraded 16.15.00 iPad baseband.
It took me a day to figure this out and I hope it helps you fix your iPhone. Comment if you have a question and I will respond to it.