Remote code execution via MIDI messages

The dot matrix is actually eight 5x8 characters, or 320 bits in total. I'm packing those 320 bits into the the 4 bits per byte that are available to us in this shell protocol. Plus, another 9 bytes for the packet header and footer. Looks like I wrote 92 in the article, I must have miscalculated that.

I'm not using the full 7 bits because figuring out a way to do so turned out to be way too hard for me, so I opted for a solution that is negligibly worse than the optimal one, in comparison to the original one.

If you're wondering about the exact algorithm, consider checking these files out, but please keep in mind that I haven't cleaned the code up yet: https://github.com/portasynthinca3/swl01u/blob/master/fun/bi..., https://github.com/portasynthinca3/swl01u/blob/master/fun/ba...

> So yeah, these [keyboard manufacturer] madlads made a shell that runs on top of MIDI SysEx messages on top of USB.

> [T]he most interesting commands that we have are arbitrary memory read/write commands. So, if we really wanted to, we could just peek and poke the memory of the synth via MIDI.

> If we wanted to, we could write these messages to a MIDI file and play it on the synth like any other MIDI file. Hey, that gives me an idea.....

> From the countless sleepless nights of digging around in the firmware I’ve discovered a function that sends arbitrary data to the LCD controller.