Come installare iOS 7 sui vecchi iPhone e iPod Touch
How can I install iOS 7 on my 4th gen iPod touch? - Ask Different
Raffaele on Twitter: "Is this the first iPod Touch 4 running iOS 7.0 in the world? Successfully dualbooted iOS 7.0 on my iPod Touch 4. Many thanks to @nyan_satan for the dualboot