[NVR-420] How to upgrade the firmware by USB flash?

Step1. Please remove all the data on the USB flash. Then put the firmware (*.bin) in the root index of the disk. Rename the firmware as "firmware.bin"
Step2. Remove all the wires connect to the NVR-420. Plug the USB flash. Press the reset button and connect the DC power.
Step3. Hold the reset button till all the LED on front panel light in green. Release the reset button and wait for few seconds. You will see all the LED on front panel are blinking green. It means the upgrade is in process. When the blinking stop, the NVR-420 will be reset to default. Please use the utility to connect and login by admin/admin and check the firmware version again to confirm the upgrade procedure.