Today,i have just got a news that the 3ds new version has been to v2.1.0-4,this update does not block any flashcard.I have purchased a r4i gold 3ds card,as the r4i 3ds offcial site doesn't released this news,so i am affraid whether this updating news is true at first,and then one of my friend told me,he has tested it.So i updat my 3DS console to the new firmware version is 2.1.0-4,however no visable changes can be found.Yet,i feel very disspoint,but luckly,the r4i 3ds card still works perfectly fine but i don't suggest anyone updates until the staff say it safe ... 
Here is the 3ds flahscard list that can run on the 3ds v2.1.0-4.They are:
1.R4i Gold 3DS
2.AK2I
3.R4iDSN 3DS
4.supercard
5.Ace3ds card
Here is the 3ds flahscard list that can run on the 3ds v2.1.0-4.They are:
1.R4i Gold 3DS
2.AK2I
3.R4iDSN 3DS
4.supercard
5.Ace3ds card