I don't know where you got mfstools2.iso, but it likely is not lba48 aware. Did you look at the sticky posts in the forum as I suggested? Look for an iso that specifically says it is lba48 aware. You didn't mention what hardware you have, but I'm assume it's an S2 running 7.x (SA) or 6.2 (dtivo). If it is anything else, there might be more work to do.