MT-card playing Pokemon X and Y error message

I have Nintendo 3DS XL with firmware 4.4.Purchased mt-card - came with (1) bluecard, and (1) yellow-card with version 1.4.I am using Sandisk and PNY microSD class 10 memory card, both 16GB.Copy Pokemon X to microSD card, insert it to yellow-card. Was able to play game for an hour, then get an error message - "An error has occurred. Hold down the power button to turn off the power, then turn it on and try again for help visit support.nintendo.com"Re-formated the card, copy Mario Cart, this game works fine. Then copy Pokemon X back to microSD, and none of the games work. Delete Pokemon from microSD and Mario works no problem.Question 1 - what is the best microSD to play Pokemon X and Y?Question 2 - I have original Pokemon X and Y. (both game requires firmware 6 and higher). Does mt-card has emulation mode (to emulate firmware 6.x) so I can play the original Pokemon X and Y.Question 3 - mt-card come with blue-card and yellow-card. when do we use blue-card again after the initial setup?Thank you in advance.

Question 1: Naturally, the best microSD to play a Pokemon would be the highest class - class 10.
Question 2: Yes, the MT-Card supports emulation of a higher firmware (emuNAND). That being said, I have absolutely no idea how to do it.
Question 3: You will use the blue card to update the cards hardware and software. This will be required to add new features etc. Keep an eye on their site for any updates.

Thank you for reply.I tried 2 microSD class 10: PNY and Sandisk - both failed (was able to play few minutes)Also tried with Kingston class 4 - Pokemon does not start, it fail immediately.Does anyone knows hot to play Pokemon in emulation mode?Thank you