This isn't made very clear - and was the source of your trouble (and mine!)

'Restore' mode is where you have a picture on the screen, showing a USB cable heading towards the iTunes logo.

'DFU' mode involves a blank screen. DFU mode is a necessary part of the process, although I'm unsure exactly what happens in this mode.

I took several attempts on my Mk1 iPhone before I appreciated this difference, although to be fair, the Pwnage tool does attempt to help you get your phone into DFU mode.

Users need to know about the two modes, and not to confuse them!

I've been using the 'modem' feature of my Nokias for years. No need to buy (or subscribe to) a USB dongle - just set up Internet Sharing via Bluetooth, and bingo, mobile internet on your laptop.

Why can't Apple manage this?