I have a 2G iPhone (Ser #87804) which (I think was originally 1.1.3). I unlocked it at 1.1.4 with ZiPhone and at 2.0 and 2.1 with pwnagetool. It's been fine for months and then a few weeks ago, after syncing the screen flashed white and then black and wouldn't come back.

iTunes recognises the iPhone and I can put it in recovery mode and DFU mode (confirmed with USB prober) but iTunes won't restore any firmware to it (iTunes 8.0 and 8.0.2, firmware 1.1.4, 2.0 and 2.1 - original and custom).

Help! Is there anyway to really get it back to factory state? I'll try anything