I got a 16GB iPhone 3GS for my b-day 2 weeks ago. And until today I decided to no jailbreak it. Well today I said why not and went ahead to use Blackra1n. I didnt update it from the box as I knew 3.1.3 is currently unjailbreakable and decided that I may want to JB later on so I played it safe and didnt upgrade. I also know that most 3GSs require a tethered jailbreak, and said if I find it too inconvienient, I'll just restore. So I go to jailbreak, install blackra1n, and cydia. After I do some stuff in Cydia, I restart my phone and to my surprise I didnt have to plug it back into my computer to jailbreak! So now I have a 16GB iPhone 3GS jailbroken and unteathered. Im so happy I just had to share Also, how do I find out what week my iPhone was made?