Thank you Christina for your friendly answer, but I did a really bad job asking what I actually wanted.
You’re absolutly right, I should use the production image, but… yeah.
I currently have a dev image rolled out in a local instance (without internet access or balenaCloud), added my ssh key to it and it works perfectly.
However, given the nature of the dev images, you can login with the user root and no password at all - even if you added an ssh key.
Now that I have a working ssh key in it, i want to remove the option to not be able to login with a the empty password for root, but only with root and my ssh key
Do you have an idea on how to get it working?
I tried following:
# remount to rw
mount -oremount,rw /
# open sshd server config
# do not allow password auth and do not allow empty passwords
# restart sshd server
systemctl restart system-sshd.slice
this did not help, so I rebooted - and still could access the RPi via ssh on port 22222 with root and no password…
Any ideas :)?