No Sound in ASUS ZenBook 14 UX433FN after installing ubuntu 18.04

I have an asus zenbook 14 ux433FN. Faced the same issue with Ubuntu 18.04 (it comes with the kernel 4.15). I upgraded to kernel to 4.20 through the "ukuu" utility and the sound/headphones seem to work fine.

Here are the commands that in case you need to update the kernel

1. Check your kernel version

   uname -r

2. install ukuu by following this link: https://ubuntoid.com/install-latest-ubuntu-kernel-ukuu/

3. update the kernel with ukuu

   sudo ukuu --install v4.20

4. reboot and check your kernel version

Note: I would also like to point out that the suspend function would not work in ubuntu 18.04 for ASUS ZenBook 14 UX433FN. It would eat up all your battery even if you are in suspend mode. The solution to that can be found in the following link: Ubuntu 18.04 - Dell XPS13 9370 no longer suspends on lid close

It seems like there is a patch for the linux kernel comming in to fix the problem soon.

https://lore.kernel.org/patchwork/patch/1022579/

So I think the two options you have is wait for the patch to hit mainline kernel, or to replace it yourself (disclaimer, I haven't done that yet myself)

Installing a bios update (available on Asus website) solved the problem for me, without any further modification in Ubuntu.

I had the same problem, but it got fixed automatically on update of the kernel from 5.0.0-23-generic to 5.0.0-31-generic.

Check your kernel using the command:

uname -r