This article explain how to create a booteable USB stick to flash an EFI flasheable file under DOS enviroment.
Is my EFI InsydeH2O?
The easiest way to figure that is looking on the "BIOS POST Screen" for this image:
Step 0 - Preparing the work enviroment
You must create a folder on your desktop to use it as workspace. I will use one named "Toolbox".
Your current Windows user account must have administrator rights.
You must have the Windows based executable file that contains the EFI flasheable file. If you don't have one, enter to Support Website page and get one for your computer. I will use one named "EFIUPDATEPACKAGE.EXE".