Well this afternoon I was trying to turn on my 3g and it was stuck on the apple logo, hard reset it a few times and the same thing kept happening. So I put it into DFU mode and decided to update to 4.0.2 instead of 4.0 because I thought there might be some benefit. Downloaded 4.0.2 and have been trying to restore using it. thanks
Were you restoring or updating through Itunes or through Shift + Restore mode to the downloaded file. The apple logo stuck has nothing to do with the 4.0 firmware.
Try pressing restore in Itunes, it will download into a specific folder and will restore it for you to 4.0.2. You can still jailbreak using Redsn0w 0.9.5b5-5. Make sure you have to point to 4.0 ipsw, you have to download the 4.0 ipsw file