When trying to update your iPhone, iPad, or iPod touch to a newer firmware IOS 8.1, you might have encountered various problems, such as error message 11, 1013, 1600, 1601, 1602, 1603, 1604, etc. These errors might tell you that your device is not eligible for upgrade, or that it’s not eligible for restore, or even that it isn’t eligible for the requested build.
this device isn’t eligible for the requested build
There are fairly common errors, and thankfully there is an easy fix. All it takes in a few seconds of your time.
There are actually two ways to fix these types of error messages. The easy way, and the long way. We’re going to have a quick look at both.
The easy way: TinyUmbrella
• Download TinyUmbrella
• Launch TinyUmbrella and go to the “Advanced” tab
• Uncheck the box that says “Set Hosts to Cydia on Exit (If you need a clean restore from Apple uncheck this box)”
• Close TinyUmbrella
The hard way: editing files manually – On Mac:
• Make sure you are logged in as administrator
• Open Finder
• Hold down COMMAND + SHIFT keys and press ‘G’
• Enter “/private/etc/” in the field and press “Go”
• Find “hosts” file in the directory
• Drag the file to your desktop
• Open it in text editor
• Remove the line that has gs.apple.com entirely or put a # at the beginning of it to comment it out
• Save the file
• Drag it back to the /private/etc/ folder
• Enter your username and password to authenticate
• Locate the hosts file in one of the following directories:
• Windows 95/98/Me c:windowshosts
• Windows NT/2000/XP Pro c:winntsystem32driversetchosts
• Windows XP, Vista, 7 c:windowssystem32driversetchosts
• Right click on it and choose “Open With…” then click on “Notepad”
• Remove the line that has gs.apple.com completely and save the file
• Once this is done, proceed to restore or update your iPhone, iPod touch, or iPad. You shouldn’t have any problems going forward.