Several models of phone out there that still only use TFTP for provisioning. Even though they have reached end of life, some of the popular ones are the Cisco 7960 and 7940.
apt-get install tftpd service xinetd
Change the configuration
edit the /etc/xinetd.d/tftp
Enable TFTP in FusionPBX Gui
Goto Advanced > Default Settings > Provision
Set Enabled to True and define the path to where the TFTP files will be.
tftp x.x.x.x get 000000000000.cnf
See the file getting requested for tftp
tail -f /var/log/syslog | grep tftp