That's a common issue on the iPhone 5. I think one solution is to use a Flex patch which forces the app in Fullscreen. I'm not sure of any other solution other than restoring, which isn't an option with the i5. I'm not sure anyone has tracked down the cause either. If my assumptions are correct, then you don't have many options outside of accepting the fact you'll have that wasted space or you use Flex to fix it. Hope this helps.