Turn off the NVS-25 using the power switch.
Press and hold the STM button, and turn the power switch on.
Continue to hold the STM button for 45 seconds.
The front-panel LED's will alternate between red and green.
Let go of the STM button and the NVS-25 will continue to boot.
The NVS-25 is now reset to default. The NVS-25 will then boot to factory settings with the default username and password.
If the reset did not work, please try the process one more time before contacting Datavideo support.