I’m not sure if it’s the fact that I’m using iTunes on Windows or if it’s because I’m with a shitty ISP, but every time I try to download iPhone software I get an error saying that the network connection was reset and the update bombs out.
Instead, I had to directly download the software from Apple’s download server, then hold shift (or option if you’re a mac person) and click on restore. It’ll ask you where your software is you want to use, and restore from there.
You can even install older versions if you want, although you might need to downgrade your iTunes as well.
iOS 4: iPod Touch 2G, iPod Touch 3G, iPhone 3G, iPhone 3Gs and iPhone 4.
iOS 3.1.3: iPhone, iPhone 3G, iPhone 3Gs.
iOS 2.2.1: iPhone, iPhone 3G, iPod Touch, iPod Touch 2G.
iOS 1.1.4: iPhone, iPod Touch.