@DoomMaster
The 'easy' way to activate the 1 meg agnus
involves installing a 1/2 meg "fastram" card
in the bottom expansion port. After a few
minor motherboard mods, the "fastram" card
will be addressed as "chipram" (check aminet
for the full instructions). I did this myself
years ago...it's easy.
The better way would be to install the ram
directly on the mobo, but I have no experience
of this...then you would have the expansion
port free for fastram/etc.
-edit-
Check here for the Rev. 6 agnus mod:
http://www.textfiles.com/computers/a500_1mb