Allegedly, on or about 08 June 2016, George N. White III sent:
I have one of the macbook pro systems with a failed (months after the warranty expired) systemboard that can't use optimus. I have to start X manually
Tangential topic reply: Depending on where you are, and how long ago that was, look into your local office of fair trading, consumer advice bureau, or what yours is called. You may find that manufacturers aren't allowed to limit their warranty as much as they have done.
Over here, in Australia, if a manufacturer says they offer a 2 year warranty, for example, that doesn't mean exactly 2 years. They're obliged to have a reasonable amount of overlap. And the kind of appliance, and its cost, get taken into consideration (what the reasonable lifespan for it should be).