Mystery dungeon: Explorers of time

I downloaded and put Mystery dungeon: Explorers of time (U) on my flashcart about a week ago (DSTT) and it's working fine.
But now I'm up to the very start of chapter 11 and whenever I try to go the part of treasure town where the Kecleon brothers are, it just freezes. I've tried turning it off, blowing on it etc. but it's still not working :/
Anyone know what the problem is?

maybe your firmware? i'm not too familiar with the DSTT

I'm using most recent version of firmware.

all i know is that the rom itself has no problem. i beat the whole thing without a problem
maybe ask someone else, cause i have yet to learn the full technical things of flashcards

Hmm...

https://www.romulation.org/forum/index.php?topic=1462.0

Tried formatting it. Still not working :(

What brand of MicroSD?

Sandisk