After lots of running back and forth to the printer yesterday to check connections and cycle power, I finally got OctoPi talking to my Ender 3 Pro. I'm still running the stock firmware but will be upgrading to Marlin 2.0 soon. I attribute all of the issues I was having with (Pi<-->printer) connectivity to power-related problems; first it was an undervoltage condition probably due to a crappy 5V PSU, and next was... maybe?... power cycle sequence. Which leads me to my question:
For those that are using the PSU Control plugin with a relay to turn your Ender on and off, are you running into connectivity problems? I'm reading that mostly OctoPi likes to see the printer on before it's connected, and turned off only after Pi is shut down. True? False? I have the plugin installed and a relay board in hand, but I don't want to install it if it's going to cause more connection problems. Thanks in advance...