Firstly, I'd like to mention that this method is not completely my own - I figured this stuff out through a little digging and adapting other people's methods to suit the AAO. To fix the audio auto-switching problem: 1. If you haven't done so already, I highly recommend using the [url=http://code.google.com/p/xnu-dev]Voodoo kernel 9.5 beta 2[/url]; I've found it improves performance (specifically over the ToH kernel installed by default with iATKOS) and fixes a few things with hyperthreading and SpeedStep if you've got that kext installed. 2. If you're using the ALC268FIX package provided in the iATKOS thread, delete AppleAzaliaAudio.kext and AppleHDA.kext from /System/Library/Extensions. You may also need to delete the "Taruga" folder (I didn't run HDA Fix, so I didn't do this step). 3. Contrary to the other method, I've found that ALCInject.kext is actually necessary for auto-switching (I might be wrong on this one though). If you don't have it already, get it [url=http://rapidshare.com/files/154468166/ALCinject.zip.html]here[/url]. HDAEnabler may also be necessary, but again, I'm not sure on this one. 4. Install AppleHDA.kext from [url=http://rapidshare.com/files/154468366/AppleHDA.kext.zip.html]here[/url]. 5. Reboot. You'll likely notice a noise coming from the speakers - that's because the microphone is enabled. Go to System Preferences, then sound. Go to the "Input" tab, select "Internal microphone" and lower the input volume all the way. That should be it! Auto-switching between headphones and the internal speakers works perfectly for me, as does shutdown.