My iphone is currently jailbroken. My current OS is 3.1 (7c144). I downloaded the blackra1n.exe file from quickpwn.com. Do I have to install 3.1.2 from Itunes so my iphone is back to stock then jailbreak it with blackra1n? or keep it jailbroken, plug into itunes, chose not to upgrade to 3.1.2, and follow the jailbreaking instructions from there? thanks