TFTP Server is useful for PXE booting or upgrade of routers/switches etc. A simple but working tftp server is available in Ubuntu is tftpd-hpa.
Install package:
sudo apt-get install tftpd-hpa
Edit server configuration:
sudo vim /etc/default/tftpd-hpa
and set your tftp root directory:
TFTP_DIRECTORY="/home/tftpd"
Manage service:
sudo service tftpd-hpa [status|stop|start|restart|force-reload]