Creating a snipplet to add to rpi imager

CustomPiOS has a tool to generate a snippet so you could add it to a json to be uploaded to rpi-imager.

to use it pass the the docker build command the --rpi_imager flag. eg:

docker run --rm -v `pwd`:/distro --device /dev/loop-control guysoft/custompios:devel build --rpi_imager

Inside the workspace folder there will be a json file that can be used to create the list of os_list. It serves to give similar functionality to This github action