Using OpenBSD to clone a Windows 10 USB bootable drive

Windows 10 allows the creating of a bootable USB drive using Recovery Drive. I don’t particularly want to have a draw full of USB sticks for all the Windows computers that I support. So I have one USB thumb drive and then copy the bootable image to an OpenBSD computer. That computer in turn is then backed up.

BSDs are different to Linux in the way they use disk labels¹:

• a is the root partition
• b is the swap partition
• c is the whole disk

So when copying a USB stick to an OpenBSD hard disk you use:

dd if=/dev/sdXc of=/your/directory/filename.img

To write an image file to a USB drive just do the opposite:

dd if=/your/directory/filename.img of=/dev/sdXc

Working out which disk to read/write

The way I do it is this.

Before plugging the disk in I run

sysctl hw.disknames

Then I plug the disk in and run it again, look to see what the difference and then just for good measure, write it down!