: Provides an extensive list of V4.02.R11 firmware categorized by hardware model (e.g., BLK5008A-S).
: Log in to your DVR/NVR and navigate to [Main Menu] > [Info] > [Version] . v402r11 h264 h265 dvr nvr firmware download exclusive
If this returns a 404, your vendor locked it. Proceed to Source 2. : Provides an extensive list of V4