@sergiosmail do you get anything when doing the following?
root@pixelboard:~# cat /proc/asound/cards 0 [AudioI2S ]: Audio-I2S - Audio-I2S Audio-I2S
If not, please check that you have enabled the kernel package
sound-mt7620 in menuconfig.
The 210-omega2-sound-max98357a.diff patch makes sure that the
snd_soc_max98357a module should get automatically loaded at startup. You can check in
root@pixelboard:~# ls -la /etc/modules.d/*sound* -rw-r--r-- 1 root root 126 Jan 30 2019 /etc/modules.d/30-sound-core -rw-r--r-- 1 root root 13 Jan 30 2019 /etc/modules.d/55-sound-soc-core -rw-r--r-- 1 root root 72 Jan 30 2019 /etc/modules.d/90-sound-mt7620 root@pixelboard:~# cat /etc/modules.d/90-sound-mt7620 snd-soc-wm8960 snd-soc-max98357a snd-soc-ralink-i2s snd-soc-simple-card
Finally, before you can play sounds:
root@pixelboard:~# alsactl init Found hardware: "Audio-I2S" "" "" "" "" Hardware is initialized using a generic method
From here on aplay and other sound tools should work
If you want more control, such as a mixer with two separate volumes for background music and game sounds, look at pixelboard's asound.conf
Also, playing mod files is fun (need very littel disk space, lots of tunes can be found online), possible with the hxcmodplayer package