3g 1600 custom
 

got iphone 3g on 3.1.3 and want to restore it to 4.1 custom .

built custom firmware with sn0wbreeze and put phone in dfu with ireb7 and tried to restore with itunes ( 11.1.3.8 ) and get 1600 error . if i restore OFW 4.1 it restores fine . is it bad firmware problem ?