How to Create a MS-DOS Bootable USB Flash Drive

1. Download the HP Flash Utility hpflash1.zip and also download the Windows 98 MS-DOS System Files win98boot.zip. 
2. Extract hpflash1.zip to any location of your drive.
3. Double click on the executable to install.
4. Extract win98boot.zip to any location of your drive.
5. Launch the HP USB Disk Storage Format Tool that was just installed. Choose your flash drive from the drop down list at the top [Device], and ensure that the file system is set to FAT32 [File system].
6. Under [Format options] check/select "Create a DOS startup disk" option. Click on the "..." button near the text box to browse to the location of where you extracted the Windows 98 MS-DOS System Files.
7. Click on "Start" button. You're done!