Brand-new SD cards sometimes need to be formatted to VFAT to work properly on Linux.
sudo fdisk /dev/mmcblk0 > t select "b" for FAT32 > w
This will convert the first partition to FAT32 and write the new partition table to the SD card.
Make sure to select the top-level disk with fdisk, and not one partition, such as
To reformat, run this.
sudo mkfs.vfat /dev/mmcblk0p1
The disk is now ready to be used.