I updated my iphone 3gs to firmware 4.2.1 and tried using redsn0w to jailbreak it. I followed the on screen prompt and it showed the pineapple logo and went through those steps. After that it went to reboot and can not boot up. The apple logo comes on for about 2 min then flashes and comes back on. I put it in DFU mode to try and restore using itunes, but it goes about 3/4 the way through and says it can not complete restore and gives me error code 1015. I think it is because i tried installing the ipad firmware so i can unlock it also. Can anyone point me in the right direction to install firmware so it will boot up again. Please let me know if you need more detailed information. Thanks.