@r2tincan - try this and update me right away on if it works so I can make it available for others. Anybody else wanting to test this in the meantime go ahead. You are testing macpro 6.1 bios and audio. Dont' do any restarts until you have completed all steps. There are 3 kexts necessary that are in the "other" folder. The EFI folder is included as well and contains an SSDT.aml file in clover/ACP/patched leave it there.
"Other" Folder contains 3 files
AppleGraphicsControl.kext <-edited kext to enable macpro 6.1
AppleHDA.kext <- patched for ALC1150
HDAEnabler1.kext <- patched for HDAudio
Step 1: into your S/L/E folder and delete those three kexts if they are present.
Step 2: In KextWizard click on Installation tab Browse for the 3 kexts in the "other" folder and select them.
Destination = System/Library/Extensions
Target disk = Yosemite and hit install
Step 3: Delete your old EFI folder and Paste in my EFI folder (if there is any system specific changes you need for your xeon in the new EFI folder that you had in the old EFI folder or config.plist do them now)
Step 4: Enable trim (speeds up drives and gives them full support in osx for native recognition) <- note will slow down boot time a couple of seconds.
In command
Step 5: In KextWizard under maintenance tab repair your permissions and rebuild cache.
Step 6: Restart your computer and test sound
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