The fixes in the 4.20-rc kernels are for other laptops, not the UX391UA. You'll need to add:
SND_PCI_QUIRK(0x1043, 0x10a1, "ASUS UX391UA", ALC294_FIXUP_ASUS_SPK
to /sound/pci/hda/patch_realtek.c
to get sound working on this laptop.
I used the 4.19.9 kernel, applied the 3 linked patches and added the line above. If you're using 4.20-rc6 / 7, you may only need to add the line to patch_realtek.c
The fixes in the 4.20-rc kernels are for other laptops, not the UX391UA. You'll need to add:
SND_PCI_ QUIRK(0x1043, 0x10a1, "ASUS UX391UA", ALC294_ FIXUP_ASUS_ SPK
to /sound/ pci/hda/ patch_realtek. c
to get sound working on this laptop.
I used the 4.19.9 kernel, applied the 3 linked patches and added the line above. If you're using 4.20-rc6 / 7, you may only need to add the line to patch_realtek.c