sudo snappy update
Starting download of ubuntu-core
104.54 MB / 104.54 MB [====================================] 100.00 % 1.48 MB/s 
Done
error from system-image-cli: ('%s exited with %s:\n%s', ['ubuntu-core-upgrade'], 1, "['/sbin/mkfs', '-v-t', 'ext4', '-L', 'system-b', '/dev/mmcblk0p3'] returned 1: , mkfs.ext2: invalid option -- '-'\nUsage: mkfs.ext2 [-c|-l filename] [-b block-size] [-C cluster-size]\n\t[-i bytes-per-inode] [-I inode-size] [-J journal-options]\n\t[-G flex-group-size] [-N number-of-inodes]\n\t[-m reserved-blocks-percentage] [-o creator-os]\n\t[-g blocks-per-group] [-L volume-label] [-M last-mounted-directory]\n\t[-O feature[,...]] [-r fs-revision] [-E extended-option[,...]]\n\t[-t fs-type] [-T usage-type ] [-U UUID] [-jnqvDFKSV] device [blocks-count]\n\nI: prepar")