iPhone 4S start over and over again since iOS9
After iOS9, my iPhone 4S start over and over again: black screen with the white apple, it is starting, then a loading bar appears. The bar loads to a quarter, then the iPhone start over, and again, and again, until it has no more battery. Tried to connect it to iTunes, tried to reinstall it completely, it doesn't work. Can't install iOS9.1 because it says my iPhone doesn't have enough memory. Ideas?
iPhone 4S, iOS 9

