Installing iOS 7
Here is how to install the pre-release version of ios7. Download the ios 7 image at https://developer.apple.com/devcenter/ios/index.action#. Make sure you pick the right one for your iphone model. The dmg file for iphone 4S is 1.16G. While downloading, backup your iphone to itunes. Don’t skip this step since you will be installing a pre-release image. Also, don’t use icloud, I learned it the hard way… Basically your iphone would freeze up and there isn’t much to do but to boot into DFU mode and burn image again… ...