Comment 151 for bug 1850439

I've tested those commands.

Before run it, I installed alsa-tools:
sudo apt install alsa-tools

then I run these commands:
sudo hda-verb /dev/snd/hwC0D0 0x20 0x500 0x1b
sudo hda-verb /dev/snd/hwC0D0 0x20 0x477 0x4a4b
sudo hda-verb /dev/snd/hwC0D0 0x20 0x500 0xf
sudo hda-verb /dev/snd/hwC0D0 0x20 0x477 0x74

Awesome, the sound is working good now on UX533FTC and Ubuntu 20.04 LTS!

It does not work after rebooting.
So, I created bash script and run it on startup.

1) Create a bash script:

nano fix_sound.sh

#!/bin/bash

hda-verb /dev/snd/hwC0D0 0x20 0x500 0x1b
hda-verb /dev/snd/hwC0D0 0x20 0x477 0x4a4b
hda-verb /dev/snd/hwC0D0 0x20 0x500 0xf
hda-verb /dev/snd/hwC0D0 0x20 0x477 0x74

2) Change the permission of the script you saved
sudo chmod 774 fix_sound.sh

3) Add it to startup

sudo crontab -e

4) Then add this to your crontab:
@reboot /path/to/fix_sound.sh