Thanks. This one was not going anywhere with me. (though to be fair i was trying with a 770)

Problem with datafiles in debs is they always first get extracted to / tree when dpkg first unpacks the deb - even if you move them to mmc in postinst (afaict). Or can this be done in preinst?

I really don't see a solution to this besides putting them all in a seperate archive that user must download to mmc. Any more ideas on this? Ideally we'd want a game with exe and libs taking only 1-2MB to be able to install on a system with <=4 MB free, while magically putting data files on mmc.

(and /media/mmcX/share is my preference as a standard dir for that type of thing)

(edit) One possibility is to split $game.deb into $game-bin.deb and $game-data.deb and make them non-dependent on each other for pkg-manager.

Users who have sufficient space could then install both debs (from website link, package-manager from repo, or install from file).
For users w/o sufficient space, the game binary would have a launcher frontend which, if gamedata not found, would prompt user to specify location of the downloaded $game-data.deb and extract (ar x) that to the /media/mmcX/share/$game directory. I know that's a bit involved, but I can't come up with a simple solution that works around the core problem of dpkg extracting all the game data to root filesystem first, before package scripting can take effect.