Xbox One owners will be able to perform an offline update on consoles with a USB flash drive and a PC with an internet connection and USB Port, according to the Xbox One support page.
The emergency offline update is intended for users having trouble downloading the system update from Xbox Live. In order to download the update offline, users will first need to know what OS their system is running. Users can then download the update on a flash drive from their PC, and transfer the files to their Xbox One. The flash drive will require at least 2 GB of space and must be formatted correctly.
Before installing the update on the Xbox One, users will need to unplug the network cable, power off the console and unplug the power cord. After powering back up — if done correctly — the system will issue two "power-up" tones.
"The first power-up tone will occur approximately 10 seconds after powering up," the post reads. "This indicates that a USB update has been detected. The second power-up tone indicates that the update file has been copied and mounted. This is important, as it confirms you have a compatible Xbox One system update based on your current build. This informs the system which build is currently installed on the console, and whether the update is compatible with that build."
The console will need to restart and may take several minutes to power back up. Step-by-step instructions are available on the support page.
Xbox One requires a launch-day patch before users can begin using the console. The patch is not tied to enabling offline functionality.
Update: The support page explaining how the offline update process works has been taken down. We've contacted Microsoft to find out why these instructions, and their associated download links, have been removed.