Imaging a Flash Drive

For a recent project, I needed to make an ISO file of a USB stick for a backup. The flash drive held the config for a ProxMox server, and I needed to be able to restore it quickly in the case of an emergency. Making best use of my Google-Fu, I was surprised to find that, while the internet had a plethora of options to offer for burning a bootable image to a thumb drive, it was rather thin on options for creating that image.

The simplest option, and I do mean simple, is to use "dd", part of the "syslinux" package for, you guessed it, Linux. It's included with most distributions but, if yours isn't one of them, you'll need to use your favorite package manager to install it.

Starting with your bootable flash drive, you'll first need to identify its address. Plug it into your Linux box and enter:

fdisk -l

Scroll through the resulting list looking for your drive. It'll be the one listed at "/dev/sdx" that's the right size.

Next, if it automounted, or if you've mounted it through some other process (i.e fstab/mtab), unmount it.

umount /dev/sdx

... where "x" is the designation of your drive.

Now, to create the ISO:

sudo dd if=/dev/sdx of=/path/to/NewFile.iso

In this case, "if" is "input file/folder" and "of" is "output file/folder". I dunno what "dd" means but it's probably something like "dump drive". If not, it should be.

To reverse the process and burn the iso to a thumb drive, again, make sure it's connected but not mounted, and enter:

sudo dd if=/path/to/The.iso of=/dev/sdx

And that's pretty much it. Imaging doesn't get much easier than that.