When I plug my iPhone into my mac, nothing happens. It dosn't charge anything, nothing gets synced, iTunes doesn't recognise anything. I have swapped the cable and tried charging my phone when it was completely out of battery. My phone charged until the phone turned on, and then as soon as it turned on, it stopped charging and my computer didn't recognise it.

I jailbreaked it using BlackRain, I have not updated to 3.1.3, I am still on 3.1.2.

Any help would be greatly appreciated.

Cheers