This is probably the easiest iTunes error to fix.
To fix this you just need to know 1 simple thing. The difference between recovery mode and DFU mode. Because that is the problem. You are trying to do a restore, custom restore, downgrade, jailbreak or something and you are doing it from recovery mode. When in fact you need to be in DFU mode.
So here is what you need to do. Grab your device and plug it into iTunes. Then press the power button (the top right button) for three seconds.
Then while holding the power button, hold the home button for 10 seconds.
After 10 seconds let go of the power button while still holding onto the home button. Do this for 10-15 seconds or until iTunes pops up with a display saying iTunes has detected an iPhone in recovery mode. (I know I said we don’t want to be in recovery mode but trust me, your not in it, iTunes just doesn’t have a prompt for DFU mode.)
And voila, you should be good to go and no longer receive iTunes error 1.
That doesn’t mean you won’t see any other iTunes errors. If you do come back here, well help straighten you out.