Iphone 3g un-jailbreak

[Muffiee]

Hi guys,

I have an iphone 3g i jailbroke on IOS 4.0 (8A293) on firmware 05.13.04 however it is pritty slow, i have heard that IOS 4.1 resolved alot of these issues so i'd like to jailbreak on IOS4.1

I know IOS4.2 has just been released but i doubt we will see a jailbreak for this anytime soon, so my question is how do i unjailbreak my iphone 3g and can i jailbreak to 4.1?

Thanks

[Cowboy]

upgrade to 4.1 save your ssh and and rejailbreak with redsnow
download the firmware and contol alt restore pc or option restore for mac and select 4. firmware do it quick before apple stops signing it.