Lane layout (as viewed from front-panel side of the board, from the "top"):

(back of board)
LANE 1  LANE 3
LANE 2  LANE 4
(front of board)

FMC layout:

(back of board)
FMC 0  FMC 1
FMC 2  FMC 3
(front of board)

Lower 16 bits of GetFlashAttributes correspond to flash
chips on the "top" of the DIMM.  Upper 16 bits are the bottom (and
are difficult to access with a scope).

Looking at the memory daughter board schematic, I believe that (as you
naturally look at the front or back of the daughter board with the
connector pins "down") the more significant byte of the 16 bits on the
powerPC is the RIGHTMOST chip of the pair.  That is: U9,U11 (back)
U12,U14 are the more significant bytes in the 16-bits.

- cpo (Dec. 18, 2007)