If you are experiencing issues with your flash cart and the Super Nt/Nt mini, there are many variables that could be producing negative results that are out of our control and have nothing to do with the Super Nt or Nt mini:
Troubleshooting your flashcart
1. Make sure your SD card is formatted correctly and try reformatting it.
a) Use an SD card formatter like this. (format type: FULL (OverWrite), format size adjustment: ON)
2. Try another brand or type of SD card. Flashcarts are known to have issues with certain SD cards.
3. Make sure your flashcart is on the latest firmware. You can usually find the Everdrive's latest firmware here.
4. Make sure your roms are original and compatible with the flashcart you are using. Each flashcart has different compatibilities (some games work, others don't, some games work perfectly, others have issues).
5. If these issues persist, please contact the manufacturer of your flashcart for support. You can find the Everdrive support forum here.