I had many testing recently. I even don't remember what I did.
Basically, I followed the GUIDE to install 10.9.4, then upgraded to 10.9.5 and made everything working except sleeping.
My laptop is E6410, i7, NV 3100. I installed Windows 7 and Mavericks. Bootloader is Chameleon. The bootloader is installed in Mavericks partition. The harddisk is MBR partition.
After I upgraded to Yosemite, the audio did not work. I tried Voodoo and others. None of them worked. Eventually, I removed Voodoo, but turned the HDAEnabler on, it works.
Later on, I tried the fresh installation of Yosemite. The trick did not work. I have to install Voodoo2.86.pkg and use HDAEnabler on. Please use pkg to install the driver. It will remove AppleHDA and install Voodoo properly. Reboot is requred. For some reason, I had to install couple of times.
Let me know what you have.
Thanks,