Greeting for the day.

I have been using https://libre.computer/products/boards/roc-rk3328-cc/ board.
I have USB to serial cable from http://shop.t-firefly.com/goods.php?id=32
I have connection and setting as per this https://roc-rk3328-cc.readthedocs.io/en/latest/debug.html
I am using Ubuntu image from http://download.t-firefly.com/Source/RK3328/ROC-RK3328-CC/Firmware/Ubuntu/ROC-RK3328-CC-ubuntu18.04-LXDE_20180605.img.xz

Still I am not able to get console on my terminal.

After logging into board, when I check, there wasn't any agetty process running for console.
Even after running picocom on /dev/ttyFIQ0, and connecting USB of laptop to putty I won't able to establish serial connection.

I also check loop backing RX/TX pin of board, In that scenario, on board port seems working fine. And also check converter with loop back and its also working fine. I had two unit of board and same thing is happening with both board.

Please suggest further action.