Problem: tftp-ing from A to B yields nothing but a timeout
  on A and a log entry in Bs /var/adm/messages:

  Jul  8 23:28:25 lodka tftpd[321]: [ID 464510 daemon.error]
  socket (delay): Protocol not supported

Solution: check tftpds root directory for world- and/or user
  nobody readability.

  ls -ld /export/install/tftpboot
  rwxrwsr-x  root distadm /export/install/tftpboot