I have a JB 3G iphone on 4.02. I read that the sluggish response that accompanied IOS 4 would be fixed with 4.1. Can anyone verify this? I also read that with Greenpois0n, we cannot unlock the phone. I am using T-Mobile and need to unlock. After jailbreaking with Greenpois0n, why can we not go into Cydia and download and install untrasnow to unlock?