Difference between .xinitrc, .xsession and .xsessionrc
I found three configuration files.
startx
How to force “startx” at startup?
Sorry if I used wrong subject, but my problem is explained completely here: https://forum.armbian.com/topic/5561-how-to-configure-scriptbincustomfex-for-spi-lcd/?tab=comments#comment-42545
How to start a second X session?
I tried to do it with the command startx 1. It seemed to flicker to a different screen momentarily, but then exited. Got the following error: