Pokemon Black 2 freezes everywhere after you get to route 7

I'm using a patched rom on CycloDS Evolution with a nintendo DSLite

Everything is fine when I started playing. But I noticed as I progressed further and further into the game, freezes happened more frequently. Usually they can be solved when I turn cheats off, but after defeating Skyla and going to the tower, not only did everything freeze when you encounter a pokemon or trainer, but it also happened if I had cheats turned off. Not just on route seven, but frequently at Pokestar studios, as well. anyone else having this problem?