How to Fix “Device Not Eligible for Upgrade, Restore, Requested Build” Error - by aby benedict

When trying to update your iPhone, iPad, or iPod touch to a newer firmware to take advantage of the untethered jailbreak, you might have encountered various problems such as error 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.

There are fairly common errors and thankfully, there is an easy fix for them. All it takes in a few seconds of your time, or more, depending on how complex you like things…

There are actually two ways to fix this. The easy way, and the long way. We’re going to have a quick look at both.

The hard way: editing files manually

On Mac:

Make sure you are logged in as the 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
On Windows:

Locate the hosts file in one of the following directories:
Windows 95/98/Me c:\windows\hosts
Windows NT/2000/XP Pro c:\winnt\system32\drivers\etc\hosts
Windows XP, Vista, 7 c:\windows\system32\drivers\etc\hosts
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.

The easy way: using TinyUmbrella
Download TinyUmbrella
Launch TU 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
You should now be good to go ahead with the restore or firmware update.