[Nuje]

At least six attempts and well over two hours of trying to update my iPhone 4 (first attempt - an "update" - failed, leaving the iPhone in some nether-state, making subsequent attempts having to be "restores").

iMac refused to success (Error 1013 - which popped up probably 90% of the way through the process). Tried different USB cables. Different USB ports. Then, tried the MacBook Air. First try went without a hitch.

This was a jailbroken iPhone at 4.1, so that may explain why the original update failed. But not sure why I couldn't get the iMac to do a successful restore...

The iPad, on the other hand: not a problem. Update went exactly as it should have on the iMac. Go figure.

 

[Nuje]

Yeah - I had read that and did comment out the gs.apple.com entries, and still had it fail two more times. But I am guessing that because I had jailbroken, saved SHSH blobs and whatever else on the iMac, something got hinky in there.

So, with that explanation of the 1013 error, that means that you can't update (assuming you've downloaded the .ipsw update file already) without being connected to the internet (?).