I do not know what is wrong and don't have any other ideas.
37-48 can by repeated without change. By deleting either the AppleHDA.kext and/or HDAEnabler. and rebooting, then installing the MB ALC887 and waiting a few moments, audio will work until reboot.
1-Clean install
2-Boot OSX volume with -x
3-MB DL and install UserDSDT/DSDT-Free
4-reboot
5-Unplug plug HDMI, MB: Ethernet- Atheros; Boot Options- 1080p, Verbose mode
6-reboot
7-MB: ALC887= NO AUDIO
8-reboot
9-DRMStatus Error
10- reboot -x
------------------------------------------------------------------------------------
11- delete AppleHDA.kext and HDAEnabler1.kext
12-reboot
13-MB: ALC887= AUDIO!
14-reboot
15-DRMStatus Error
16-reboot -x
17-Delete AppleHDA.kext (may not have waited long enough after install??)
18-reboot
19-Desktop
20-MB: ALC887= NO AUDIO
21-Reboot
22-DRMStatus Error
23-Reboot -x
24-Delete HDAEnabler1.kext
25-reboot
26-Desktop
27-MB ALC887= NO AUDIO (may not have waited long enough after install???)
28-reboot
29-DRMStatus
30-reboot -x
31-Delete AppleHDA.kext and HDAEnabler1.kext
32-reboot
33-Desktop
34-MB: ALC887= NO AUDIO (may not have waited long enough after install???)
35-reboot
36-DRMStatus
--------------------------------------------------------------------------------------------
37-reboot -x
38-Delete HDAEnabler1.kext
39-Reboot
40-Desktop
41-MB ALC887= AUDIO! (After few mins) (flickery task bar (happened upon HDAEnabler delete/reboot also)
42-reboot
43-DRMStatus
44-reboot -x
45-Delete A
ppleHDA.kext
46-reboot
47-Desktop
48-MB: ALC887=
AUDIO! (After few mins)
49- Insanity diagnosis
Ring any bells? Could I provide an IOReg/other info at any of these steps to help?