*** Moderator Note *** This method of using VoodooHDA for onboard audio (HDEF) and AppleHDA for HDMI/DP audio (HDAU) can be applied only to chipsets that support Haswell and Broadwell. Sandy Bridge, Ivy Bridge, Skylake, KabyLake, KabyLake-R (and likely future chipsets) all have an integrated HDEF (with both onboard audio and external audio) with no separate HDAU.
I was finally able to fix my audio issues with the UX303!
I have used VoodooHDA for Internal Speakers / Combo Back Headphone Port, Internal Mic and Combo Jack Mic port. I managed to fix the jack sense thanks to Mr Gfoury and victor123ong for their posts and patches. The UX305 shares the same codec as the UX303 so I used the patches and adapted to it to the UX303.
I however wasnt able to get HDMI audio working with VoodooHDA so I edited AppleHDA's Plists so that it would only use the internal graphics and I edited VoodooHDA's plists so that it would only use the standard sound card. Major props to this gentleman here for his guide
Could you please provide some more detailed instructions? Is loading the two audio kexts be enough or I still have to have AppleHDA before hand? Thank you, I come from the UX305F ElCapitan are topic and having issue with HDMI audio.