On Docker this was easy, but as a Linux noob I can’t seem to figure out what file needs to be changed to get the deconz-gui service to start up with Info L1 debug logging turned on by default. Can anyone tell me where I need to add that parameter?
So you mean for classic OS ?
You can run it with command line too Debugging 101 · dresden-elektronik/deconz-rest-plugin Wiki · GitHub
If you want to make it permanent, can edit the service config file, cf Update deCONZ resets customized port · Issue #561 · dresden-elektronik/deconz-rest-plugin · GitHub
You can too use Overriding file (explanation on the same link)
I am using the default conbee rasbian image file from:
https://phoscon.de/en/conbee/install#raspbian
I already tried to find the config file, but /etc/systemd/system/deconz.service does not exist?
Right I have it on /usr/lib/systemd/system/deconz.service
Thanks, found it! I guess I should have used "find / -name ‘deconz*’. 
The Linux filesystem always confuses me…
I assume the service files will be overwritten with an upgrade of the deconz package?
right but not if you use “Overriding file”