Reply To: Settings for HDMI and Composite

[gizmo98]

In my opinion raspbian detects hdmi or sdtv if hdmi_force_hotplug=0 is set. runcommand.sh checks with tvservice --status if sdtv or hdmi is set.

https://github.com/retropie/RetroPie-Setup/blob/master/supplementary/runcommand.sh

runcommand.sh does something like this:
starttype/parameter 1 – if hdmi change resolution to CAE 1 (VGA), otherwise (SDTV) do nothing.

It is possible to add other CAE modes/resolutions. You can get a list of all supported modes withtvservice -m CAE.