How to Fix iTunes Error 3194 During iOS Update on Your iPhone, iPad or iPod Touch:
You’re just trying to update / upgrade the firmware but iTunes keeps throwing up this error. In most cases, it’s because of a simple problem with the hosts file. Here’s how to fix it:
For Windows, navigate to C:/Windows/System32/drivers/etc/ and find the file that’s named “hosts”
For Mac, the file is in /etc/
Open the file in Notepad (or any other text editing software) (for Windows users, open this with Administrator Privileges)
You’ll mostly have this line at the bottom of the file:
Either comment this line out by typing a single ‘#’ (without the quotes) in front of the line (before 74) or remove the line entirely.
Now, save the hosts file and then try updating your iPhone through iTunes.
In most cases, the error shouldn’t pop up now.
Again, if you’re lucky, this should work. To me, this method never worked but then, I had my iPhone jailbroken too many times. So that’s when TinyUmbrella comes to the rescue.