[UPDATE] Ha! Nevermind, they are the same, Hex Editor told me that I was missing a "00" - now everything "checks out". Checksum pun.

I've made it! I'm far from sharing anything, but I finally managed to read AND store a full game! Everything is based on the speedtest for the serial interface over USB and another file storing sample for C. I had to fiddle around with buffer sizes and remove a string in a hexfile editor, but it counts, the came works :) I get 4 times the same checksum for 4 cartridges, but somehow I get a different checksum for a downloaded ROM, and the files look very different.

- Anyways, probably best to go to bed now :)