NSC Solution F1, wont initialise after downgrade the firmware to V14.39

Panel F1 with firmware V15.08 is working very slow and button response is to long, and buttons wont response to command.
In conversation with support from nsc, solution is to downgrade firmware to last stable V14.39.
After confirmation that panel is successfully updated firmware. I repeat all procedure again because this board contain redudant procesor.
Next step, booting new firmware, video begin in this moment.
-panel scan all internal modules then
-check the detectors on loops
wery strange is behavior to start all loop sounders wile initialisation process?!
The panel stuck in these step.
I reboot panel many times and any time panel stuck in this step.