Coolio, I heard bad SD cards cause bricks with A9LH2 consoles have the stock SD card, 2 have an 8GB microSD card, 1 has a 32GB Sandisk SD card that I've had since 2014, and the 3 N3DS XLs I recently bought, I'll give them each a 32GB microSD card (SanDisk Ultra 32GB microSDHC UHS-I Card). So I mostly stick with Sandisk Ultras, they're $12 on Amazon, a bargain.
I have an 128GB microsd for my N3DS. That was an upgrade from 32GB, which was an upgrade from 16GB.