If you want to your own .7z archives from .nds files (e.g., for backing up your game collection), simply select the .nds file, right-click → 7-Zip → Add to archive → choose 7z format and maximum compression. Do Flashcarts Support 7z Files? No. Flashcarts like the R4, DSTT, or Ace3DS+ require .nds files to be placed directly on the microSD card. They do not have onboard decompression capabilities. Therefore, you must extract the .nds file from the .7z archive before copying it to your flashcart.
For advanced users, you can also use the command line: 7z to nds converter
for %i in (*.7z) do "C:\Program Files\7-Zip\7z.exe" x "%i" -o"%i_extracted" While .7z offers the best compression ratio, you may also encounter: If you want to your own