TFTP uses UDP port 69 and requires no authentication —clients read from, and write to servers using the datagram format outlined in RFC 1350. Due to deficiencies within the protocol (namely lack of authentication and no transport security), it is uncommon to find servers on the public Internet.
But it may be that there is a TFTP implementation that uses TCP, and if so, I'm afraid I have no exposure to it. Domain Name System (DNS) is traditionally the protocol referred to when discussing protocols that use both TCP and UDP. It doesn't use these at the same time, mind you. But different functions within DNS might call for TCP vs UDP. TCP vs. UDP: Understanding the Difference Dec 17, 2018 System Configuration Guide for Cisco Unified Jul 20, 2020 4.6.4.3 Lab – Using Wireshark to Examine TCP and UDP
Oct 27, 2015
Differences between TCP and UDP - GeeksforGeeks
TFTP udp port - Cisco Community
Jul 20, 2020 4.6.4.3 Lab – Using Wireshark to Examine TCP and UDP Jun 26, 2019