[sneak]

This small patch of mine to raspbian may be useful for you, then:

https://github.com/RPi-Distro/pi-gen/pull/207

The minor downside is that you have to build the image yourself, but fortunately that is a single command once docked is installed.

[swinglock]

I must say it's silly we can't be trusted with a simple way to drop in a shell script on the SD card that runs at boot as root in rasbian.

I don't even understand the idea that it could be bad for newbies to maybe mess up. The whole point of the RPi was to give students a small, cheap, easy to repair computer with low-level features to learn with.

[sneak]

Yeah, the project is sort of a mess maintainer-wise, but at least it is straightforward to modify/rebuild.