I actually have this flashcart. The issue with it is that it drains a heap of battery, so it's not ideal if you're just playing NDS stuff.
I also tried to fit the entire DS game library on an SD card for this flashcart, and the main challenge was figuring out how to organise the files so that it wouldn't crash the cart.
Basically you can't have everything in the one folder cause I think it tries to load everything all at once, so I had to separate it by a-z. And even then, I think I've limited to around 100 files per folder.
I also tried to fit the entire DS game library on an SD card for this flashcart, and the main challenge was figuring out how to organise the files so that it wouldn't crash the cart.
Basically you can't have everything in the one folder cause I think it tries to load everything all at once, so I had to separate it by a-z. And even then, I think I've limited to around 100 files per folder.