Manual workaround method

You can manually work around the PXE reboot issue by creating the task sequence steps and groups and using the procedure that the Deployment Pack uses to solve the problem.

The solution also involves creating a custom script that will connect remotely to the Configuration Manager server (with appropriate credentials), accessing WMI, and resetting the PXE advertisement for the specific computer running the task sequence.

However, there is no need to do this work manually since the Reboot To PXE / USB custom action takes care of setting up the task sequence for you.

Related reference
The Reboot To PXE / USB custom action