Hi Hugo.

No, it doesn't grab all ram. Get too close to the limits and linux gets very upset.

Doesn't that basically summarize what mlord said: Grab all RAM minus a preset offset (which might or might not be proportional to the total amount of system RAM).
Let me ask it the other way: If I would successfully add more RAM to my MkII(a), patch the boot loader and get the Linux kernel to recognize and use it (so that it is reported in /proc/meminfo), would the actual player binary automatically allocate more RAM for buffering? Or would it basically stick to the amount of RAM it would expect on a MkII(a)?
Also: I seem to remember that someone from empeg (you?) said that the MkIIa board design actually provides the soldering pads for additional RAM (on the back side of the board?), is that right? Or was that on a non-public board design?

cu,
sven