New to flashcarts, not new to emulation. Quick question about corrupted saves.

So I found my old DSi after forever and wanted to try it out again. Got one of the Kaicosoft Pico DS carts and all has been well. Was so impressed with the build quality I decided to get one of their Super-GBA carts. Think it runs superfw. After playing and saving through my games for several hours without issue, while saving for the last time the screen went black and the audio went into a short endless repeating loop. I'm familiar with crashes so restarted, knowing there was gonna be a problem and yeah the save was corrupted. Reloaded from a backup and ordered a better microsd card so not a big loss.

My main question is - was this this simply a cheap or sketchy microsd card? Or does this sort of thing just happen occasionally with these carts? What can i do if anything to prevent corrupted saves going forward?