first of all what are the games that you are trying to play?

first advice,
format your micro sd with the panasonic sd formatter
download a new firmware and drag and drop it to your sd card
make sure your sd card have sufficient space

 

I just bought one myself and saw this foreign screen after turning the DS on.
Would somebody mind linkin to the firmware? Or is it here on the forum?

Nvm, found it here.

 

Try these steps I compiled maybe they can help you.

How To Troubleshoot Your Flashcart:

STEP 1: Make sure you're not using the card reader that comes with the flashcart. Buy your own. Always use the "Add/Remove Hardware Safely" function before removing the reader.
STEP 2: Check your microSD card for smudges on the contacts. Clean with a QTIP. You can add a bit of alcohol onto the QTIP, if wanted.
STEP 3: Check your Flashcart for any abrasions or smudges on the contacts. Clean with a QTIP. You can add a bit of alcohol onto the QTIP, if wanted.
STEP 4: Possibly, your Flashcart is not making perfect contact the DS. Try the "Paper Shim Trick" to close the gap and make the space tighter.
STEP 5: Copy all of your games and saves off your microsd card to your computer (BACKUP). Download the latest "Panasonic SD Formatter" and do a full format with this application. Install the latest firmware again from a different/reliable site. Then add on your games and saves to the newly formatted card.
STEP 6: If the latest firmware doesn't work sometimes downgraded firmwares can achieve working results. Try downgrading, if it doesn't resolve just go back up to the latest firmware again.
STEP 7: There are times where the official firmware for your specific cart isn't up to par with the alternatives created. Try a legit alternative firmware for your flashcart. eg, (DSTT/R4 -->YSMENU), (Acekard--->AKAIO), (M3 DS Real---> Sakura) so forth..
STEP 8: If you're using cheats maybe they are faulty. Get rid of them and get them from a reliable source.
Or just dont put them on period.
STEP 9: Possibly the "GAMES/ROMS" you have are faulty. Obtain ones from a new location...
STEP 10: Try another DS. If possible.
STEP 11: If all else fails, get a new Flashcart and/or MicroSD Card from a reputable site.

Tell us if it works or not~ Good luck.

 

maybe the OS have been broken. you should updated into new version.