i can't get redsn0w to work (OSX version & current version). i get to the part where it goes thru the instructions to put the iphone into DFU mode (or whatever). i press the relevant buttons at the appropriate times, and it appears to start doing something, but then sits and waits at "waiting for reboot". nothing happens after that. i know the iphone is in DFU mode as when you start itunes it tells you. i've tried this 3 times now and it keeps stopping at the same point. any ideas ?