I have a iphone 3g without a sim card that I'm trying to jailbreak so that i can use without sim card. I can't seem to get it into DFU mode trying dozens of times. (I've had no problem on any other phone) so I wanted to use DFU-IPSW. I made the IPSW with redsn0w, but don't know how to proceed from there. When I select IPSW it says it is not supported by this version of redsn0w. any advice?