I have a giveaway usb stick and when I plug it into my computer and run lsblk it shows two block devices, i.e. sdb and sdc. sdb of them contains almost all the free space ( ~15G) and the sdc one is very small (32M) and contains stuff like images of the company who gave the usb stick away. I would like to get rid of the sdc one (more out of curiosity). However, these are apparently not partitions on the same hard drive (otherwise lsblk would show something like sdb1 and sdb2, right?).

Last but not least I can't even run fdisk /dev/sdc as it's apparently a Read-only file system.

Can I get rid of this sdc device or at least wipe it clean. And what are the inner workings of this? Is sdc a second physical drive?

  • lsusb should give you more info on what the system sees, but yes, they are two separate disks. A quick google search turns up a lot of other drives that are created this way as well. – bgregs Jan 16 '19 at 13:49
  • Do you know the manufacturer of the USB stick? – Bodo Jan 16 '19 at 14:02
  • @bgregs lsusb gives the same output whether or not the usb stick is plugged in. Am I missing something here? – xel Jan 16 '19 at 17:40
  • @Bodo Unfortunately I don't know the manufacturer. – xel Jan 16 '19 at 17:42
  • Maybe you can use the USB IDs to find out the manufacturer. – Bodo Jan 16 '19 at 18:11

There are USB sticks that present itself as two drives: a CD-ROM (readonly) and a mass-storage device (read/write). This was invented to allow auto-starting an application when the USB stick is plugged in on a windows system.

There may exist a removal tool from the manufacturer. Example: Sandisk U3. Search for keywords: sandisk remove u3 launchpad

  • Thanks for pointing me in the right direction. After a bit of searching i compiled the u3-tool from the source but it still says Read-only file system. Other users seem to have the same problem. It might work on windows, though.. – xel Jan 16 '19 at 18:04
  • I once had two U3 USB sticks from Sandisk. IIRC on one of them I removed the CD-ROM partition with Sandisk's Windows program. I don't know the open source tool. You might be able to check from the contents of the partitions if it really is U3 or something else. Unfortunately I have lost my U3 stick, so I cannot tell you what you should look for. – Bodo Jan 16 '19 at 18:11

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