@Mrakobijes said in trying to use KMS driver yields no composite video output (Raspberry Pi 4):
dtoverlay-vc4-kms-v3d-pi4,composite=1
This looks like a mis-spelling, it should be just:
dtoverlay=vc4-kms-v3d,composite=1and you should start with stock config.txt, instead of the one you're using, which has too many overclocking options which may conflict.
Note that this configuration is not fully supported by RetroPie yet and for the KMS driver is recommended to use an up-to-date Linux kernel/firmware.
You