I didn't have modified no other kexts from 10.9.1 in 10.9.2 (since 10.8.x i have only these modified kexts: AppleHDA, ACPIPlatform and AMDRadeonX3000), so it seems to me that in 10.9.2 Apple has changed something else in AppleHDA that broken audio.
I'm guessing two alternatives:
- Apple has modified the way that HDA binary has been patched. (Since Lion until 10.9.1)
- Another system kext is causing problem... (IOAudioFamily maybe?)
I have no more idea with AppleHDA. Everything is 'right'. :/