Video with 3.5 jack and RCA

If I connect Raspberry Pi over RCA to old CRT TV, is there a way to switch resolution to correct value? Current OSMC installation works with HDMI cable and Full HD TV. I guess 1920x1080 resolution is stored and it will be used for RCA/CRT output ==> no image on TV.

No, composite output is always output at a fix resolution in NTSC unless you change this in your config.txt. There are a few different threads on this forum where people got this working. Off the top of my head I think the first thing is to make sure you are using the correct cable as there is more than one pinout used on TRRS to RCA cables. You also might want to try adding “hdmi_ignore_hotplug=1” to your config.txt.

I hope Kodi user interface can be shrunk to PAL resolution.

The first two sections in the article I hyperlinked show how to switch output mode and aspect.

No problem, but see here:
https://discourse.osmc.tv/t/osmc-skin-4-3-aspect-ratio-support/86436/3