Mery pas iphone 3g hai us me ios 3.1.2 tha or kl me nay us ko update krny ki kosash ki or mery pas ios 4.0 ki update ipsw file bhi mojood thi lekin jb me nay shift or restore button ko dbai tu restore start ho gaya or aik error aa gaya error (3004) us ky bad iphone ki screen par usb or itunes ka logo aa raha hai plz koi mdad kr day i will be very thankfull if any one tell me the way to update thanks please full process