let me guess what you did.
1. it came and you got excited.
2. you put in your micro.
3. you put it in you 3ds andcyou got an error message.
You need to put kernel files first!
go 2 the site printed on the cart
show error means you card has to be updated to support your console, just remember the case in the future, never update you console before update your card, you need a dsl or other console you r4i 3ds can work on to update your card. if your card is r4i sdhc 3ds, just download the latest kernel v1.56b(the r4i sdhc team has put the update files on the kernel folder) , goodf luck~