As far as anything knows, an sd card in a usb reader may as well just be a usb flash drive, at least if it's a simple reader with just an sd slot. If it's a more complex reader with slots for many types of cards, each treated as a separate drive, it might be different. Just my experience. I use the sd reader that came with my dstwo flashcard, and it's treated exactlly like a usb thumb drive, anyway.