When I try to enter DFU mode using pwnage or quickpwn my iphone screen just says black. Both apps recognize and say it successfully entered DFU mode but itunes won't recognize it. Has anyone else had this problem or know what I should do? I'm using 2.2.1 and I haven't had my iphone jailbroken since 2.2 originally was released. And only for about a month before I restored it back to apple settings.