I recently got a 3GS and when I plug it into iTunes I am prompted to download and install the 3.1.3 update (the phone has 3.1.2). But when I try to download it, at some random point during the process, the download fails because of an "unknown error". I am unable to resume the download and have to start from scratch again. I have tried several times but have always gotten the error during the download. Any one knows what may be happening? Is there a way to download this update via the browser or torrent instead of iTunes? I know I can option click on the Update button in iTunes to select a downloaded file. But from where can I get it? Thanks.