im on iPhone 3GS. firmware 4.2.1 on baseband 6.15.00. ive tried everything. used tiny umbrella to kick it out of recovery, no fix. tried recboot to exit recovery, it just reboots back into recovery. redsnow isnt allowing me to get into DFU mode, saying an error occurred. i try to restore to custom firmware on itunes but it says the firmware is not compatible, yet i have tried 3 different ones. i tried pwnage, no fix. i cant even get into DFU mode, and i know im doing it right.