Just want to add my 2 cents. I'm run my gigabyte p55 board with i5 for about 4 years now. Worked my way up from OSX 8 to the last version of 9. Other than the boot 0 problem which I fixed, never really a problem. Then I did the last security update last night and i had the hanging "/". researched and found this thread and unplugged my 2TB time machine. Booted fine. Added the single device line mentioned here to my chameleon plist and now I'm back in business. Looking at upgrading to 10.10 now.