Last month I ordered a copy of the Nintendo DS Browser (by Opera) from Amazon. When it arrived I was all ready to start syphoning porns from the very air we breathe, but my dreams were to be cut short, as I discovered that the Opera browser requires a Memory Expansion Pak, which, while included, was incompatible with my *original* DS. It would only actually fit in a DS Lite. Through observation I deduced that the physical interface was basically the same and that it would probably work in my original DS, if it weren't for the lip that was on the top of the cartridge preventing me from actually pushing the thing far enough into the DS for it to make electronic contact. I decided that it was time for a hardware hack.
All I needed to find was a file to rip off the lip so that it could be jammed in there. I didn't have one, of course, so I got the closest thing I could find: a giant bolt that Jp had left over from a table he built.
After filing the lip off, my room smelled like burnt plastic all night. Oh well.
Then I tested that it would fit into the DS by half-inserting it upside down to see if the lip would fit past.
I then realized that if I actually put the cartridge into the DS, I would have no mechanism with which to remove it. I tried taping a twist-tie onto the cartridge but that proved pretty weak; I then realized that putting packing tape on both sides of the cartridge would be the best.
I then jammed it the rest of the way in with the back end of my stylus.
It works wonderfully. There may be other DS Lite-only expansion cartridges out there, and this technique will probably work on those. Tell me if you have any luck.