Microsoft released a Rollup Update for Configuration Manager v1702 this week to address multiple issues. One specific issue that affected many deployments was related to operating system deployment:
Starting with System Center Configuration Manager, version 1702, unknown computers that are started from media or PXE may not find task sequences targeted to them. This issue may occur if the Previous button on the “Select a task sequence to run” page is selected on the unknown computer.
There are already great examples of how to install this update, but there are a couple of key gotchas I ran into during deployment.