How To: Restore your iPhone when you get the Error “Unknown Error 3000” or “An unknown error occurred (4027)”
Here’s another tip that probably will not benefit many of you, but hopefully for the few who run into this problem this post will save you some fraction of the time I wasted figuring this out.
So today Apple released the Gold Master (GM) build of iOS 7 to developers, allowing those of us with developer accounts to get the final build a few weeks earlier than the rest of the world. The only problem? When I tried to install the latest build in the normal fashion, I received an error message. TWO in fact, at different points.
“Unknown Error 3000” or “An unknown error occurred (4027)”
I kept getting these errors on two different machines, so I was pretty sure it was not the fault of the computer I was using (and that same computer had installed all the previous betas just fine). After wasting a couple hours Googling this I found a number of purported solutions, and even ended up eventually restoring my iPhone back to iOS 6 following iMore’s wonderful guide. I do not however think this actually helped solve my problem, as I still got the same error messages when attempting to install the GM Build once I was downgraded to iOS 6, using the “hold down the Option Key while clicking the ‘Restore’ button in iTunes” method, then navigating to my downloaded IPSW GM build. However, if my below solution does NOT work for you, then I say go ahead and try it again after downgrading to iOS 6.
Anyway, what I eventually found was that for some reason or another, despite having the latest sanctioned build of iTunes running on my system, I needed to download the beta of iTunes from Apple’s site in order to update my iPhone to the GM build.
Luckily this part is easy. Just scroll a little bit down past the iPhone builds on the iOS 7 developer page, and you’ll see it. Simply download and install the iTunes beta, then follow the standard firmware update method mentioned above (holding the option key and clicking “restore” in iTunes, then selecting your downloaded IPSW GM build).
Hopefully that helps. Let me know if it does, and if it doesn’t, and something else eventually does, please post back your experience.