Ubuntu – Read Only usb stick that won’t let me do anything to it


Somehow I messed up and accidentally made my usb stick into a read only file system. I have tried a bunch of things to delete the files, including the basic (rm -f myfile) and attempting to allow writing (sudo chmod +w myfile) and then deleting, but none of this seems to work. Any ideas on what I can do. I don't have anything on the usb stick that I need, but I don't want to throw away an otherwise perfectly good piece of equipment.

How can I make it work? Am I going about this completely the wrong way?

Best Answer

Commands like rm and chmod are done on a mounted file-system. So if the file-system is read only those do not work. What you need to do is to mount the file-system as writeable.

Some USB sticks have a switch on the stick to mount them read-only. Maybe that is the reason. It could also just be broken or damaged due to not correctly umounting it.

Before you do anything: copy the files over from the stick.

If it is not a hardware switch unplug and plug the USB stick and issue a

dmesg | grep -i panic

This will show you any panic messages. If you are seeing alot of them related to the USB stick and if it is a FAT partition you can use dosfsck to fix it.

You can find out how it is mounted with


and use

dosfsck -a /dev/sd{xn}

to fix an MS-DOS partition table or sudo mkfs.vfat /dev/sd{xn} to format the disc. Where {xn} is a letter and digit you got with the mount command.

You can also use gparted to format it by the way.

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