Seems like an issue I've seen brought up on a couple of lists recently by A1 board owner.
Basically, it seems to be this.
OS4 will support graphics cards a,b,c and shorlty later d, e
Linux which currently is used til OS4 is released, supports a, mostly b, d, e and f
Now if you buy the A1 with card c, it's not much use under Linux. Same if you get card b, but it kinda works under Linux. Now you could get card f which might be the best to use under Linux but will have no OS4 support.