Reformat USB stick in Linux

Here’s a follow-up to the blog post Create a bootable USB stick in Linux.

The first time I reformatted my USB stick from bootable to a normal file-storage device, I followed some other instructions, but now instructions worked.


1. Insert the USB stick.

2. In terminal, issue:

dmesg | tail

3.There will be the description of the activities of the last active device. The device name will be between brackets as [sdd], [sdc] or [sdb]. See what you got and remember it.

4. Unmount the device. It should work by issuing in terminal:

sudo umount /dev/sdb

The sdb bit should be your own device of course. However, sometimes the command doesn’t work. I had to use the graphical file manager to unmount the device.

5. Reformat by issuing in terminal:

sudo mkdosfs -F 32 -n 'Label' -I /dev/sdb

The -F 32 can be omitted, but it ensures the most Windows-friendly format.

The ‘Label’ gives the device a name. You can have ‘MyUSB’ or such, if you like.

6. After the last command has done its thing (may take time), remove and reinsert the stick to test the result.

NTFS File System

When the aim is to format the stick as ntfs instead of msdos file system, step #5 is different:

sudo mkntfs -L Label -I /dev/sdb -F

Note the little differences from step #5 compared to msdos file system:

  • Label is without quotes
  • With ntfs, -F means “force” (to override an error message) rather than “format” (try mkntfs without -F and see what you’ll get)

All the other steps are the same.

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