This does appear to be some kind of bug. Disabling TFTP crashed GUI regardless of which section I went to. Expounding on this link:
Here are the commands to get the GUI back up, note this changes all templates to use http even if the GUI does not reflect that.
[root@server]# mysql
MariaDB [(none)]> use asterisk;
MariaDB [(none)]> select protocol from endpoint_templates;
±---------+
| protocol |
±---------+
| 2 |
| 1 |
±---------+
2 rows in set (0.00 sec)
MariaDB [(none)]> update endpoint_templates set protocol =2;
MariaDB [(none)]> select protocol from endpoint_templates;
±---------+
| protocol |
±---------+
| 2 |
| 2 |
±---------+
2 rows in set (0.00 sec)