@ekramulhaque maybe you should pressed Ctrl + C several time, then you can enter another prompted console displayed as :
hisilicon #
After you entered this console then you can see what you typed will be echoed back to your screen
Screenshot_126.jpg This my DVR console without interrupting Ctrl + C
And then 2 photos below show up in DVR HDMI display (no pressed Ctrl + C)
IMG_20190819_193309.jpeg is DVR display when booting
IMG_20190819_193331.jpeg is DVR display after booting when console ended with :
Starting kernel...
Your wire connection is fine because you have got echoed data from the serial.
The echoed console seems normal.
In my DVR when I turn the DVR on the same time I press Ctrl + C in keyboard, Then I can get another console command prompted :
hisilicon #
You should pressed the Ctrl + C several...
Near the audio port is UART0 as you can see in my uploaded image.
Then you should soldered 2pcs 1K 0603 resistor at orange square in my picture.
Or you can shorted it by tin, but I think it will more difficult than soldering 0603 resistor.
If you don't have 0603 resistor you can shorted it.
I...