Do you mean DOS or an NT command prompt? AFAIK, most BIOS updates are done in either DOS or GUI Windows. A command prompt only NT is a bit tricky, and not very useful anyway. A DOS booting USB stick ...
Most IT professionals carry a bootable USB with recovery software, Antivirus scanners, Bootable Linux, etc. But the problem is that they need multiple USB drives for each image. Here is a solution – ...