Creating a MS-DOS bootable flash drive

Guide to creating an MS-DOS bootable flash drive using Rufus for tasks like BIOS updates, and how to boot from it.

Booting MS-DOS from a USB drive can be useful for applying BIOS updates and other tasks.

Required Tools

• USB flash drive (32GB or smaller)

• A Windows 7/10 PC

Creating the drive

• Download the Rufus tool from rufus.ie

• Launch Rufus

• Under “Device” select your USB drive

• Under “Boot selection” choose “FreeDOS”

• Click START at the bottom of the window

• Double check you have selected the correct drive and press OK to proceed

• When the status bar says READY, the process is complete

• Copy any files you will need in DOS to the flash drive. If you are applying a BIOS update, copy those files now.

• Eject and unplug the flash drive

Booting to the drive

• Connect the flash drive to the target PC and power it on. Go into the BIOS (Typically F2/Del/Esc) and set it as the primary boot device.

• On newer systems, it is necessary to enable CSM / legacy boot mode as shown.

• If successful, you will be greeted with the familiar old DOS prompt.

• Use the dir command to confirm what files are on your USB drive.

• Update .bat files can be executed by typing the filename.