How do I restore ios4 and JB?

[DragonFlare]

I have an Jailbroken, Unlocked 3gs with iOS4.
My headphones' mic button won't work, but I found that it works on other 3gs's. So I wanna Restore mine to iOS4 and JB it again.
Questions are:
-How do I restore (no shsh, cydia won't offer to save them)
-how do I activate (in order to JB)

Thanks a LOT!

[neodude237]

Without the shsh files for any iOS, you're stuck right now. Apple stopped signing 4.0.1 as of last night, as far as activation goes, you'll need whatever sim card corresponds to your official carrier (ATT if you're in the US)