Back in the days when floppy disks were still being commonly used, flashing your motherboard’s BIOS could only be done by booting the computer into DOS. When DOS is booted up on the computer, you’d probably have to switch to the floppy disk that contains the BIOS update file. Unlike today where updating a modern BIOS is far easier and convenient and you can update the BIOS directly from Windows using the software provided by the manufacturer, or simply put the BIOS file onto a USB flash drive and the inbuilt flashing tool inside the BIOS will recognize it.
If for some reason the software provided by the motherboard manufacturer is broken and you’re not able to update the BIOS from Windows, or your BIOS doesn’t actually support flashing from any other medium apart from a floppy drive and DOS, you can still do it from DOS by booting up the computer with a USB flash drive instead of a floppy which is far easier. The most popular and easiest ways are to simply install MS-DOS or FreeDOS onto the USB drive, copy over the required BIOS file and flashing utility from the manufacturer’s website, boot to USB and flash the BIOS from there.
Rufus is a small utility that helps format and create bootable USB flash drives, such as USB keys/pendrives, memory sticks, etc. It’s also a useful tool to help install different versions of Windows via USB and can also check USB devices for errors. It is a small, single and self contained portable executable file and the user interface resembles the Format tool in Windows.
Rufus has the added bonus of giving you the choice of installing either FreeDOS or MS-DOS onto USB for BIOS flashing. Simply plug the USB flash drive into your computer, run Rufus, select the device that you want to install DOS onto, make sure the file system is FAT32, check there’s a tick next to “Create a bootable disk using:” and select either FreeDOS or MS-DOS from the drop down menu. Finally click the Start button. Rufus used to come with a separate version for FreeDOS support, but it’s now integrated as standard
2. WinUSB Maker
WinUSB Maker is by Josh Cell Softwares who produce some very useful Windows tools such as Advanced Tokens Manager and WinOwnerShip, and this tool can install the setup files for Windows XP up to Windows 8 setup onto USB, install the GRUB loader onto USB, create a full backup and restore of USB devices, and also do what we’re looking for, install MS-DOS onto a USB stick.
Like the other tools, WinUSB Maker is a standalone tool (although it does require the .NET Framework version 4 to run), simply launch it after inserting the USB drive and select it from the drop down in the Welcome screen. Then click on MSDOS to USB down the left and click the “Make USB Bootable” button, and accept the data will be lost warning. After a few seconds, you’ll have a DOS USB ready for the BIOS files.