... no configuring at all in cmdline.txt is needed for sound. The following is with the KMS overlay enabled: [ray@pi4 ~]$ cat /boot/cmdline.txt root=PARTUUID=d905149e-02 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200 ...