Let me start out by saying I am no expert when it comes to flashing video card so I am reaching out in seek of wiser council. I have recently come about acquiring a Sapphire 6870 video card and which I am currently running of a mac pro 5.1 the card does not boot with the typical Apple logo boot screen nor can one choose a boot drive while holding down the option key. I have read through scores of postings across the internet suggesting there is a way of flashing this card to enable the boot screen option etc while using the newer Mac operating systems eg Yosemite etc. Here is the particular Sapphire model I have http://www.newegg.com/Product/Product.aspx?Item=N82E16814102948. Any helpful advice will be greatly appreciated.