I had a thought ages ago about how I could use the link cable
facility on the gba to port down data from a pc for testing purposes,
but I thought at the time I'de have to wait for some kind of "dev
cartridge" to be invented by a third party. So I pretty much forgot
about it all..

However, despite knowing about the hardware feature for ages I simply
cannot add up :) The MultiPlay feature of the gba which downloads a
section of the game to another linked machine - wouldn't that be just
great to have a link cable gba -> pc, so you can download home dev
games, a la WonderWitch on WonderSwan.. It's only 256kbyte but hey,
I've coded games in 4k, and I'm easily pleased :P

hmm, guess it's buying a jap one and getting out a soldering iron
time :)