where do I have to place the DDF file to get it loaded at startup?
On classic OS (not dockers)
All DDF coming with deCONZ typically reside in
/usr/share/deCONZ/devices/generic/on a Linux system and are loaded first. However, files residing in the home directory of the user running deCONZ (e.g./home/deconzuser/.local/share/dresden-elektronik/deCONZ/devices) will override the pre-packaged files to allow users to amend and keep their own files if desired.
Else just try to create one, you will see the path choosen by deconz on the editor title bar.
what settings do I have to do to get DDF files working at startup?
Set the status to “gold” . But it s brutal, you can select the level in Panels / Control / DDF
To start use “basic” as mode.
Is there a naming convention for DDF files?
I think not yet. Try Model-name_device_type.json like other sml001_motion_sensor.json, it’s more usefull to put in the good folder.