One of the largest needs to use a bootable DOS USB is to update drivers or a bios. But there are many functions within DOS that you simply can’t easily get to with full windows. Creating a DOS bootable USB Flash drive is not very complicated.
Windows won’t allow you to select the “Create an MS-DOS startup disk” option when formatting a USB drive – it’s grayed out. Instead we can use Rufus. Rufus was created by Pete Batard, and can make this task simple. It can also be used to create a Bootable USB version of a given distro from an ISO file.
How to create a DOS Bootable USB Flash Drive that can ultimately be used to Run DOS from USB, using Rufus.
Note! Your USB drive will be formated! Back up any important files on the USB drive first.
2. Connect your USB drive to the computer and select it in the Device box.
3. Ensure that the “Create a bootable disk using:” checkbox is enabled and FreeDOS is selected from the dropdown menu.
4. Click the Start button.
Finally. When it finishes, restart your PC and set your BIOS to boot from the USB device, reboot and enjoy, or if you created the boot drive because you have a DOS-based program to run, copy the files over in to the root directory of the USB drive, set the BIOS to boot from the USB device, reboot and that’s all.