Hi, I have an iPhone 3g which I'm trying to bring back to life. I did an update from 3.1.3 to 4.1 awhile ago and it stopped mid way. Now when I try to restore it gives me error 6. Tried DFU, tried special DFU, tried loading custom firmware in dfu, nothing worked. Here's a restore log when I try to restore stock 3.1.3.

2012-02-12 20:48:56.680 [5488:1560]: restore library built Sep 14 2011 at 01:30: - Pastebin.com

Thanks in advanced.

This is a hardware error -- indicative normally of a corrupt NAND. It's attempting to write to free space and failing. Unfortunately, this really can only be repaired by either dismounting and replacing the NAND chips on the logic board, or by replacing the logic board in its entirety.

You've done the only obvious things that can fix this -- DFU restore, etc., and if that doesn't work you're pretty much out of luck.