I have a 3GS jailbroken with blackra1n on 3.1 but I want it to update it to 3.1.2 custom. I downloaded the custom 3.1.2 for it but after the dfu and shift restore and select the custmo 3.1.2 it says it can't restore my iphone on itunes....itunes is 9.2 v.

I have a 3GS jailbroken with blackra1n on 3.1 but I want it to update it to 3.1.2 custom. I downloaded the custom 3.1.2 for it but after the dfu and shift restore and select the custmo 3.1.2 it says it can't restore my iphone on itunes....itunes is 9.2 v.
Or should I updated with 3.1.2 from apple and jailbreak again!!!!
LOSTTT