So there have been many updates to the audio since the 1525_codec and the AppleHDAPatcher that were included in the ever-so-popular drivers pack. Since then the Internal Microphone has been enabled as well as the External Microphone, switching to both the left and right headphone jacks for headphone use (just not both at the same time…yet), the sliders for the Internal Mic and External Mic which allows for less background noise when using the Microphone, and all while the Internal Speaker works beautifully. But of course you can’t get these updates with the previous codec dump so it is time for a long awaited update to the site.
To get the new audio kext working, you will need Kext Helper and AppleHDA.kext which can be found here. Just delete ALCinject.kext and AppleAzalia.kext beforehand and then load the new AppleHDA.kext with Kexhelper and restart. Upon restarting, you should find everything working great.
***In the rare case that this does not work for you, try Richard’s instructions in the comments***
(Richard: Thanks! Now I can rock out with audio out and blow my speakers.)