OSS on HP Envy

[Bahamut]

Hi! I'm trying to make the audio work properly on my fancy notebook. Since I had no success with ALSA now I gave a try to OSS.

Notebook: HP Envy 13-ab004ng: https://www.amazon.de/gp/product/B01MAYC6HK
Operating system: Elementary OS (Current version is based on Ubuntu Xenial)
Sound card: see the detailed hardware info later.

Problem: After installing Elementary OS (with ALSA), when I used headphones the sound was crackling. I tried EVERY hack on the internet related to ALSA and Pulseaudio, (Including the buffer size changes, module parameters, etc.), but nothing helped.

Then I installed OSS4, but it didn't recognize my sound card. I noticed that it has a USB audio module so I tried that and it worked nicely. Now I use OSS + Pulseaudio with this USB device: https://www.amazon.de/gp/product/B013FW002W

With that external USB device the sound is perfect, but is there any way to make the built-in audio work? I don't care about HDMI, just would like to have the headphone output function properly.

I've attached my hardware details in a text file.

Many thanks!