Animal Crossing new leaf update error?

I wanted to try to play my old Animal Crossing new leaf cassette again, but after the update I get this error message:

I don't know what to do, I also tried to clean the cassette, but it still didn't work.

It's not my Nintendo because I already have a new one and it works perfectly.

Go to the Nintendo E-Shop on your 3DS and download the update there manually. Then it should work.

I already did the update so the other way and I have to reset it somehow so that I can do it in the e-shop but I don't know how

I just downloaded it, but thanks anyway