I have restored to 3.0 with iTunes 8.2.1 and at the second try it worked.
(SOLVED): With 3.0.1 firmware
Then, in Redsnow 0.8 for Windows everything runs fine until it freezes at various stages in "Uploading ramdisk" (on PC) showing "Downloading Jailbreak Data" on iPhone. I followed the iClarified "How to Unlock/Jailbreak Your iPhone 2G on OS 3.0.x Using RedSn0w (Windows)" Tutorial.
I selected the "iPhone1,1_3.0_7A341_Restore.ipsw" file.
Also tried to unplug/plug the cable without success.
Tried already 10+ times...
Any ideas, please...