So I took the plunge and updated to the official 4.0 in hopes a jailbreak would be released similar to Spirit. I know the new PwnageTool works on iPhone 3GS with old bootrom that was previously jailbroken. Mine used to be till i officially updated to 4.0. Cani downgrade back to 3.1.3, jailbreak and then update to custom 4.0 with the new PwnageTool? If so, how? If not, do I just have to wait till they release a jailbreak for stock iPhone 3GS with 4.0?