Now the 3DS system firmware has been updated to V9.0.0-20, but it didnt block flashcarts, the supercard dstwo still work quite well on the 3DS V9.0.0-20 .But if your supercard dstwo can not work after you update 3DS system , here is the tutorial to fix this kind of problem .
Firstly prepare these things you need
1*Nintendo 3DS Console and a DS Lite
1* Supercard Dstwo Card(make sure you get this one : Supercard DSTwo)
1*MicroSD Card Reader
Step 01 , download the latest DSTWO EOS here : DSTWO Eos v1.11 .
Step 2 , after download , you will get a .zip file , unzip it.
Now open “DSTWO_v1.11_2012_1224_eng” folder and copy all files into sd card .
Step 3 ,back to the website, click and download where it says “firmware v1.25 ”
After it’s done downloading, open it.
Now open “eng” folder and copy the one file that’s only there. (eg. dstwoupdate.dat)
Copy it into the micro SD card alongside with all the other files you’ve already copied into it.
Finally , you should get the content in the sd card as follows:
Step 4,Then put the microSD card into the DSTWO and insert the flashcart into a DS Lite. You can’t do this step with a 3DS.Insert the DSTWO flashcart into the handheld and load up the flashcart.
A dialog box will ask you “Update system Beta 1.25, OK(A) or Cancel(B)”,Press “A” to start the update.
Now wait for it to update itself showing a progress bar, as the picture shows . After the update is done, the update file is automatically disappear.
Step 5, turn off the handheld and remove the flashcart and insert it into your 3DS.On your 3DS, it appear ALEX RIDER STORMBREAKER THQ and load it.
Congrats, you DID it! Now , you can enjoy your games !