hi guys hope someone can offer some kind of help. i have a 2012 macbook pro, the original hdd is in the optical bay with an sad in its place. the other day i got the flashing file on a grey screen. pulled the ssd out and put an old hdd in its place and disk utility can see it and allow me to format, so by that I'm guessing that the ribbon and data connection on the logic board are both fine. used a data to usb cable to plug my ssd in to my air and see if i could get any data off it, everything is there as expected though so i plug that in (usb again) to my pro, turn it on and it boots up fine. so, ssd works, sata port works, they don't work together?