I have a jailbroken iPhone 3GS running iOS 3. It is locked to a network in the UK but i am able to use it on other networks because it is jailbroken. What i am trying to do now is update the iOS to iOS 6.1.3 without locking it up again. I tried using redsn0w to upgrade while protecting my baseband and with all the instruction videos i have gotten to the stage where it uploads kernels etc and then it says it is restoring to iOS 6.1.3 - Waiting for device. After about 5 minutes, an unexpected error (2831) comes up and it doesn't restore. how can i fix this error and get my device to upgrade without locking up.

Please Help!