Hi,
I had the same problem.
When the screen is off your Raspberry is unable to receive edid information from the screen, resulting in no (or bad) picture.
You need to download the edid info into a file and edit config.txt for the Pi to load the info from the file on startup, instead of trying to get it directly from the screen.
Check this: https://kodi.wiki/view/raspberry_pi_faq#tv_is_not_detected_unless_powered_on_first