Strange...
HDMU make two attempts to write system time to vfd after start, and another one when going to deep....
Try this binary from zip:
Put the file from zip to /usr/sbin ,make rights to 755, start it by typing : /usr/sbin/aotomtd 30
It will become a daemon and writes system time every 30 seconds to vfd until you shutdown or reboot your stb.
Typing without Parameter the daemon will be ended.