When I plug in the USB cable between Raspi and Ender the Arduino and the LCD are powered up (the Enders power supply is off). That makes sense if you want to flash the Arduino but not in all other cases which is 99% of the time.
The Raspi is supposed to stay turned on all the time.
I thought about disconnecting the power lines in the USB cable. Has someone else had the same problem and has a different solution?