is it going to be possible to use hdmi-cec (or bluetooth) to power on or off the ppm620 or are there fundamental technical obstacles that would prevent this?
They tried CEC and there were a technical problems and this feature was turned off.
Long story short the HDMI device would send a signal to PPM to check connection even though the HDMI device didn’t need the PPM to turn on, causing the PPM to partially boot, the light engine would turn on but the fan wouldn’t and a few devices over heated causing the light engine to burn out I believe. They will not turn on this feature again.
For turn on by Bluetooth, I don’t think this can work, device needs to be on first for the Bluetooth to be working. It is why the remote works off of IR in order to power the device and then reverts to Bluetooth for better functionality. If they found a way to have BT always on it would drain the battery just sitting there.
I believe some people have tried programing other remotes such as Logitech but not sure if they have successfully mapped the power button.
Hope that helps