Raspberry Camera V2 does not work

Hello,

I am trying to use a Raspberry cam V2 on the CSI port with the RockPi 4 on Debian Buster.
I activated the overlay imx219, but cant get it to work.

using test_camera-rkisp1.sh in console fails (command unknown)

I also cant find the camera using OpenCV.

What am I missing here? The documentation in https://wiki.radxa.com/Rockpi4/hardware/camera/ is unfortunately not very detailed. Please help.