Note: As of June 17, 2010, the Retail Snow Leopard Installation Guide includes these updates. If you followed that guide after June 17, 2010, you will already have these updated kexts and therefore should ignore this guide.
With much excitement, I bring you this update guide to finally resolve the audio issues in Snow Leopard. Included are 6 kexts, 3 of which replace the dreaded VoodooHDA.kext. The other three included kexts are merely updated versions of previous kexts, though they do have their own benefits; the new fakesmc.kext is placed in /Extra/, the new VoodooBattery.kext is simply updated version, and the updated VoodooSDHC.kext works with 10.6.4.
The included kexts are fakesmc.kext, VoodooBattery.kext, VoodooSDHC.kext, AppleHDA.kext, HDAEnabler.kext, and LegacyHDA.kext. AppleHDA, along with HDAEnabler and LegacyHDA, fix the issue where the audio wouldn’t work properly after waking from sleep. Plus, the internal microphone is now completely functional. It’s also worth noting that, while both headphone jacks work, they will not operate simultaneously; If both headphone jacks are occupied, the system will default to the second/middle headphone jack.
To install the kexts, download the Snow Leopard Update Pack. Then copy the 3 kexts in the “Extra Kexts” folder to /Extra/Extensions/ located in the root of your Snow Leopard partition. Next, Kext Helper the three kexts in the “Kext Helper” folder. Also be sure to run a Tag Cache Rebuild while in Kext Helper. Finally, reboot and reap the rewards of fully functional audio, working SD Card reader, and updated Battery Meter and fakesmc.kext.