Use your PC to grab your mandatory system update ahead of time and be ready for launch day.
Updating an Xbox One using a USB stick allows Xbox users to avoid possible network connection during the day one rush. Since the Xbox requires a mandatory out of the box update, pre-downloading an update helps guarantee you'll be able to play games with your Xbox One as soon as possible.
Microsoft has pulled the customer support page that offered an option to download Xbox One’s day-one patch on a PC to update your console via USB.
Microsoft Pulls Xbox One Offline Update Page
A Microsoft representative provided the following explanation to IGN:
“The site was not an alternative way to take the Day One update and customers still need to connect to Xbox Live for the update. Because of the complexity of this customer support process we’ve actually removed the page and we will work with customers directly to make sure they have a smooth experience.”