Issue:
When PXE booting after an upgrade to Configuration Manager, PXE timed out with error 0x102.
reviewing the smspxe.log revealed "no advertisements found"
reviewed imaging task sequence and boot.wim boot image
found task sequence had not been associated with new boot image
Resolution:
Open Config Manager Console
Software Library
Operating Systems
Task Sequences
right click the task sequence - properties - advanced tab, ticked "Use a boot image" then browse to the boot image.
redeploy the task sequence to all workstations and unknown computers.