I have installed developers version of iOS 4.0 on my iPhone 3GS, so I am unable to downgrade or upgrade to any version of iOS. Any idea what to do as I am unable to either jailbreak or unlock. Appreciate all the help
Did you figure it out? Please let us know.
You got no more other options, Just Download another fresh copy of iOS 4.0 and Install into your Iphone using Itunes. You can download it from here http://download.imodzone.net/. Goodluck!
You can downgrade only if you saved your SHSH blob on Cydia.
Here is link with proper procedure:
I tried it, it not allowing me to even Jailbreak!!