RockPi4b and RPI camera v1.3 cannot open /dev/video0

I’ve tried a number of things. Most recently have motion installed. All tools consistently get ‘cannot open /dev/video0’

I’ve tried 2 different RockPI4Bs with 2 different cameras

I’m running Debian Buster

uname -a

Linux rockpi4b 4.4.154-112-rockchip-gfdb18c8bab17 #1 SMP Thu Jan 21 04:50:13 UTC 2021 aarch64 GNU/Linux

cat /etc/issue
Debian GNU/Linux 10 \n \l

even
“ffplay /dev/video0” returns
“Not a video capture device. /dev/video0: No such device”

but when I: “ls -lsa /dev/video” I get:
0 crwxrwxrwx+ 1 root video 81, 0 Sep 13 20:54 /dev/video0
0 crwxrwxrwx+ 1 root video 81, 1 Sep 13 20:54 /dev/video1
0 crwxrwxrwx+ 1 root video 81, 2 Sep 13 20:54 /dev/video2
0 crwxrwxrwx+ 1 root video 81, 3 Sep 13 20:54 /dev/video3

any ideas what I might have wrong?