Hello!
Recently I had some issues with my iPhone 2G running on 3.1.3. Lot's of lags, random resets and shutdowns. I could bear it until two days ago - suddenly I lost all of my contacts. I decided - no big deal, I'll just restore them via iTunes. To my surprise it didn't work. Tried it again to no avail. I decided to reinstall the firmware.
I had IPSW for both 3.1.2 and 3.1.3 and decided to try and downgrade it to 3.1.2. iTunes did it's job restoring, then I proceeded to redsn0w. It somehow didn't work, my phone ended up in recovery mode. Did it all again - restore then redsn0w. It bricked my phone badly though. Redsn0w got something wrong again, phone ended up in recovery mode but this time it is not recognized by my computer and let alone iTunes.
I tried plugging it in three different computers (Mac at MacStore, Linux and two computers with W7) and not a single one detected the phone. W7 does detect an USB device but describes it as unrecognized/broken device. Linux doesn't detect it at all (no change in lsusb after plugging it in).
Is there any way to un-brick my phone?

Have you tried booting the phone in DFU mode? It's made in such a way that you should still be able to boot to DFU specifically for this sort of thing. I think that may be your only shot.

If putting it into DFU is power for 3s, then add home for 10s then release power and keep holding home for approx 15 seconds then it didn't do anything useful. Still not recognized :/

DFU mode will result in your phone at a black screen (NO connect to iTunes logo) but connected to the computer, with the backlight on. If there is anything on the screen, you're not in DFU. It can be tricky to get into DFU mode the first time if you haven't done it before, but you absolutely need to be doing this restore in DFU mode. If you have the 'Connect to iTunes' screen, you're in recovery mode and your restore will not work.

1) Plug the phone into the computer.
2) Turn the phone off.
3) Hold the power button and the home button for 10 seconds (seems like a long time, but count in your head.)
4) Release the power button and continue holding the home button for 15 seconds.
5) Your computer should recognize the device in DFU mode -- the backlight will be on but there should be nothing displayed on the screen.

Hey!
Took me a while to reply I had a similar error two days ago and was forced to check in here how to fix it This time though I remembered to post thank you for your reply It really saved my device. AGAIN!