I was on the same boat with you that have problem with gpu. I solved it with 14,2 smbios.
But I saw something strange...
I make backup almost every day with CCCloner.
The Backup Disk didn't boot with previous OS 10.10.2 for restoring my basic system before solving the problem.(Booting from this partition of course)
I believe that Apple's "boys" have locked something with OSX Recovery update, because I made it earlier and then make a backup before updating my system.
Anyway my UNTOUCHED 10.10.2 Backup Partition doesn't boot anymore after updating. Maybe needs 14,2 smbios.
But why? Hmm?
Think about it...