iPhone 3GS, new bootrom, 06.15.00 Baseband

A friend has given me his 3GS to have a look at as it has got stuck in recovery mode and he couldnt get it to go back to normal.

It was originally running 4.1 and jailbroken. It also had the 06.15.00 baseband on it, it was later upgraded to 5.0.1 using a custom FW in snowbreeze as to not mess with the baseband. All running perfectly. Couple of days ago he had left it on charge and come back to it to see it on the connect to itunes screen.

I have now had a look and have tried restoring with custom 4.1 and 5.0.1 FW's with no luck. I have tried using Fix Recovery from within redsn0w with no luck. I have also tried using fix recovery in Tiny Umbrella with no luck either. It just keeps coming back to the connect to itunes screen.

iTunes gives no errors at all when restoring, just completes fine and then back to square one. Have I missed anything or is there anything else I can try?