Arrg r/o

First time I ran into dd: failed to open ‘/dev/sdX’: Read-only file system was shortly after playing with my first Raspberry Pi and it had me completeley frustrated. Gparted, fdisk, and windows could not switch the r/o bit off. Through my searching for answers as to why this happens I came across a lot of speculation from failing SD, SD reader firmware -> SD, obscure permissions issues, and what I have found to work is as follows.

Make sure system is not auto mounting USB, I choose to just stop my display manager sudo systemctl stop lightdm <- or insert your active display manager.

lsblk

sdd 8:48 1 14.6G 0 disk

├─sdd1 8:49 1 100M 0 part

└─sdd2 8:50 1 14.5G 0 part

sr0

Make sure you select the correct drive

sudo dd bs=32M count=50 if=/dev/zero of=/dev/sdd

Now you can use fdisk to create new partion table and mkfs.

If dd still complains and wont write zeros to the drive than there is another option.

sudo echo "0" > /sys/block/sdd/ro and repeat the dd command from above.