Hi @tooz
Thank you for repliyng.
I'm using official 2.1.6 Debian 10 image.
It came out that it was a cable issue, with a physical (15 to 22 pins) ,adapter the screen now works and I'm able to use rpi 7'' display.
By the way, the panel-asus-DSI1-overlay is not present in overlay folder. I still would like to use the CSI connector without the adapter. Would it be possible to attach rpi screen to the 15 pins CSI connector? What changes do I need to do in dts?
Many thanks.