02-10-2020, 05:20 AM
I think some clarification of device naming may be needed. Whether an DS card appears as /dev/sdX or /dev/mmcblkX depends on whether it's attached through a USB adapter or a native interface. For a native interface like in the PinePhone, boards such as the Raspberry Pi, or some laptops, the SD card appears as /dev/mmcblkX. A USB adapter translates between native interface commands and USB storage device commands, so the computer sees a usb storage device /dev/sdX. If you look at dmesg immediately after plugging in the card you should see which device was added.