Hello @efe
Which device type and balenaOS version are you using?
Let me also add that it looks like a previous response from the Balena team member ( Problems adding dtparam and dtoverlay variables in /boot/config.txt - #3 by shaunmulligan1 ) indicates that the dtparam=4_0_inch on a separate line should be equivalent to dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch, however this is not the case for the screen I am trying to get working which is documented here https://www.waveshare.com/wiki/4inch_DSI_LCD.
Yes,
dtoverlay=vc4-kms-dsi-waveshare-panel
dtparam=4_0_inch
should be equivalent to dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch as per the official Raspberry Pi Foundation documentation: https://www.raspberrypi.com/documentation/computers/configuration.html#part3.2
If i just use a vanilla install on raspberry pi (not using balena) and use dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch in config.txt the screen functions as it should.
As per the documentation you shared, it seems that you require both dtoverlay=vc4-kms-v3d and dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch, so the correct value for the config value should be:
BALENA_HOST_CONFIG_dtoverlay = "vc4-kms-v3d", “vc4-kms-dsi-waveshare-panel,4_0_inch” which should result in:
dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-waveshare-panel
dtparam=4_0_inch
if you are using balena supervisor version 16+. This is highlighted in the docs.
Hope this helps. Let u know how it goes!