devkitPro

I just ran your test code on a DSi using EzFlash Vi cart - using my HomebrewMenu (which is the one you download, without the change you made) + fix (#include <stdio.h> to fix the iprintf issue) I get the same results as you. Running your code on desmume and your code acts just like on hardware. Mind...

That's the power socket, it's not a USB port.

I asked about this on the #DSDev IRC channel a while back, and the answer at the time was "it's not possible within the toolchain at the moment", but looking at the current tool chain it is possible, and I'm trying to find out how to do it now with some experimentation. I know it's a part of the act...