because my port/board is a completley differnet
machine than say a "walnut". It boots differently, installs differently
has support for different MBR, partitions and bootlabels, a different
set of "standard" devices, in fact, the only thing in common is the cpu :-)
While it is easy enought to replace the "walnut" definitions for evbppc
it is not so easy to support more that one of these at once from the
same source base. Subdirectories based on boardtype would make this easy
(which is what I did) - but I'm sure there would other ways too.