In case your iPhone starts working abnormally then in this situation it becomes important to restore its data by using Apple software update Tool. But this is also correct that after performing this entire data from memory card will get flushed away. But this will resolve the software issues that are plaguing the iPhone. In the meantime, you may come across some critical error message that disturbs when user try to restore iPhone. As a result iPhone error 1603 gets flashed.

iPhone error 1603 can be fixed, but for that it is important to follow some important steps as described below:

1. Restart your computer, this is because sometimes the driver or program may get conflict and by simply restarting Mac or Windows computer this problem may get resolved. In this situation it does not matter if your iPhone is plugged in or not while reboot. While performing this you can also try to update iTunes to new version.
2. Try to plug iPhone in another USB Port; USB port might not be getting enough supply that might be reason for error message. Then restart your computer again and check if your problem gets resolved.
3. If the problem still exists then user can take out the SIM card from the iPhone before it gets restored. This will really work but why and how it fixes the problem nobody knows. But on the whole this will resolve iPhone error 1603.

Then at last plug the SIM card back again in your iPhone and then it will work properly. In order to remove the SIM card user can insert thin paper clip into the hole next to the SIM tray. Press it until the SIM card comes out of it. Now you can easily plug your iPhone into computer and then restore iPhone backup. Then at last put the SIM card back after disconnecting it.