I will write a howto when i figured out how to get the newest DNSmasq Version running on my unraid.
For everybody who cant wait, here you can see what is in my DNSmasq Config, to be honest i dont figured it out myself but it was part of a Article in a German Computer Magazine:
port=0
log-dhcp
enable-tftp
tftp-root=/mnt/user/tftp
dhcp-range=192.168.2.0,proxy
pxe-prompt="Press F8 for Menu",5
pxe-service=X86PC,"Start from HDD",0
pxe-service=X86PC,"Start desinfect",ct/pxelinux
It enables TFTP and sets it root directory to the user share i have created for it (in my case a cache only share).
The DHCP Range needs to be adjusted to your need, also DNSmasq runs in proxy mode.
Hope that helps anybody.