How can I reformat microSD cards that were created read-only?

Question

My company was burning some microSD cards (4000 of them) and the multi burning machine we were using gives us the option to make the microSD read-only.

I didn't know this was possible, but apparently it flips a binary switch in the microSD card.

We now need to reformat all 4000 of the microSD cards and start fresh. We cannot format them because they are read only. I am not using a SD adapter so the possibility of the lock switch is a non issue.

Gparted cannot format them and running this command:

sudo mount -o remount,rw  /media/48EC-B32A

… returns this error:

cannot remount block device /dev/sdb1 read-write, is write-protected

Is there any way to force format these or are they permamantly gone?

Answer 1

The SD card should be unmounted before attempting format.

You will probably need to use mkdosfs

for FAT16

mkdosfs /dev/sdb2 -F16

or for FAT32

mkdosfs /dev/sdb2 -F32

Answer 2

I have found more information on this:

SD cards have a physical lock, to write protect the card. MicroSD cards don't have the lock, but the SD adapter has it, and it can lock-unlock the card.

So, try to put the card in an adapter and slid the lock a few times, leaving it on unlocked.

Answer 3

Sorry, for previous answer, I mixed up!

Can you use the something like HirenBoot CD?

Maybe that helps.