SD2VITA card adapters are prone to being defective.
In my case it was because the cartridge wouldn't go deep enough into the Vita.

I redesigned the plastic shell to fit the components better and actually work.

Assembly should be done as shown in the pictures:

1. Remove the components from the defective SD2VITA
2. Place them onto the BACK side
3. Glue de FRONT side onto the BACK matching the pins

(I believe this is only compatible with SD2VITA 5.0, as it doesn't have the spring for the microSD)