Hello all, I recently got a iPhone 4 GSM. So I want to set it up and stuff. I am not super sure how to upgrade from my version that came with it (4.2.1) to 4.3.3 so I can jailbreak and stuff. Can anyone please provide me with a guide or something? I keep getting errors when I do it and I changed some lines in the hosts file and still nothing. Please help me, thanks.