PfSense DHCP option 66,67 for Windows Deployment Services (WDS)

If you have error using PfSense DHCP and on another machine a WDS server

PXE-T04: Access violation

PXE-E36: Error received from TFTP server

PXE-M0F: Exiting 

Use need filename in DHCP settings for WDS service with two slashes, like this