Nes_Snd_Emu VS cartreader

If LGPL2.1 is acceptable, Nes_Snd_Emu would be an option to look at. (actually looks like that's a copy of Blargg's Nes_Snd_Emu, maybe modified; I didn't check).

This particular copy—which was $38 shipped; I probably could've done better, but it was convenient!—appears to have been owned by a Shin Sakuma (佐久間伸 Sakuma, Shin) who put more than a few hours into it judging from the saves. (Which I backed up using my Open Source Cartridge Reader, in the interest of preservation. 😌)

I use my Open Source Cartridge Reader to read/write N64 controller paks. (And read/write save data from cartridges.)

In the long run, another solution might be to buy/build an Open Source Cartridge Reader and use it in combination with one of the more readily available modern flash cartridges.

I'm not from Germany (I'm from France) but I did modify my Nintendo 3DS with something called Gomode9 to dump my DS and 3DS games, I did bought an external Blu-Ray reader BP50NB40 which can be used to dump PS3 games with a tool called ps3-disc-dumper and I built a Sanni Cart Reader (https://github.com/sanni/cartreader) to dump other kind of cartridge for older consoles.

if your into soldering and have other retro games you want to look into the sanni cart reader https://github.com/sanni/cartreader

If you can solder, sanni cartreader is probably the best way to go. Otherwise, you can pay to have one built.