I have bought an iPhone4 with iOS 4.3 and I would like to upgrade it to 4.3.3 to get a untethered jailbreak. The problem im having is upgrading to iOS 4.3.3, I got the file "iPhone3_1_4.3.3_8J2_Restore.ipsw" from a friend who used it to jailbreak his fone which came with iOS 4.3.3 so I assume the file is not corrupt. The process I follow when I attempt to update is, plug my iPhone into iTunes, then I shift+click on update and point to the ipsw file I mentioned previously. It gets to a point where it tries to verify the file with apple servers and I land up with the error in the subject. How can I get around this problem? Ive searched abit online and seen some posts about tinyumbrella, do I need this to update? Its a brand new iPhone, never been used before.
Thanks for any help!