Rufus is a small program that you can start directly from DoS to convert a simple flash drive into a fully bootable USB.
Configuring the program is as easy as inserting the device you want to format, marking your favorite options and clicking "Get Started". Just be ready for your new bootable USB DOS drive in just a few seconds.
Rufus is a very small, light, supportive and easy-to-use tool. If you want to start your computer in DOS for a reason, it is one of the best ways.