Successfully funded, thanks for your support!
The cartridge is funded, thanks! Now I'll finish the software (besides the already working menu, I have some good ideas and suggestions from people what features it should have, like an additional file browser for SD2IEC integrated in the menu, some useful MIDI tests etc.) and prepare the production, I'll keep you informed of any progress. I'll open the github repository in a few days, after cleaning it up a bit. Planned shipping is in August.