I installed Ubuntu Gnome 17.04 with overlayroot on a USB pen drive and set in /etc/overlayroot.conf: overlayroot="tmpfs" to use tmpfs as overlay filesystem.

That works very well. However, I want to hardware-protect that Ubuntu is read-only, therefore I want to use the hardware-protected read-only mode of my USB pen drive. If I activate the hardware-protected read-only mode, I get the following error message if I boot:

error: failure writing sector 0x1088808 to `hd0'.

Press any key to continue..._

Grub2 starts successfully.


If you hardware-protect the USB pendrive (for example if there is a microswitch like on many memory cards), you will have a read-only system.

If correctly configured it will work, (but obviously read-only). I think the simplest way to make a read-only USB pendrive is to clone from the iso file to the pendrive. This is a reliable method and it works for all hybrid iso files, and all current Ubuntu (and Ubuntu family flavour) iso files are hybrid iso files.

The iso 9660 file system from the iso file will be cloned without any modifications, and it is a read-only file system. There is a built-in method for running the read-write part of the system in RAM.

In linux you can clone with the Ubuntu Startup Disk Creator that comes with Ubuntu version 16.04 LTS and newer versions, Disks (alias gnome-disks) and mkusb.

In Windows you can clone with Win32 Disk Imager.

  • I accepted your answer, because it answers the question. However, my problem is more complex, therefore I posted a new question with the whole context [askubuntu.com/questions/937380/… – user3734670 Jul 18 '17 at 14:56
  • @user3734670, I will browse to the link, and see if I can help you with your more complex problem. – sudodus Jul 18 '17 at 14:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.