Again answering my own questions:

PCA wrote:
Quote:
The board adds 4 identical banks of 16MB, and duplicates the bank0 set currently present on a MK2A. Obviously, this isn't going to work all that well. The idea is that each bank can be disabled by means of a switch on the memory board, so in the case of a MK2A you would turn off the first bank. This would still give you 64M, as the original memory would be used.


And elsewhere I found that RA3 needs to be jumpered over from the main board to enable the final 16MB (to 64MB). The other RA{0,1,2} lines appear to already be present from the test pads.

Now to hook it up, with photos along the way..