I have never used “sudo systemctl start OpenSprinkler” to run the firmware. After you run the build script (build.sh ospi) it will usually generate a script in /etc/init.d and auto-start the firmware. If you don’t want it to auto start, you can also go to the firmware folder, and run it manually by:
sudo ./OpenSprinkler
I am not sure where you get the instructions for using sudo systemctl to start the firmware — it’s certainly not in the instructions we published here:
https://openthings.freshdesk.com/support/solutions/articles/5000631599-installing-and-updating-the-unified-firmware-on-ospi