Hi, I am a newbie to jailbreak. I have an iPhone 3GS. Forecast v1.2 gives the following details about my phone Baseband: 05.12.01 Bootloader: 6.4 Model: MC137 Jailbreakable?: Yes (with Spirit/JBme) Unlockable?: Already Unlocked Tethered?: Maybe - Depends if Refurb BootRom: 359.3.2 Now, i want to upgrade to iOS 4.0 or later. Question is a) Is it possible b) If yes, how do i do it. You will need to give me a step by step instruction. Don't want the phone to turn brick! Many thanks in advance.