How to boot surface pro from USB
You can boot your surface pro from USB drive by the following way:
1. Enter BIOS/UEFI and change the boor order to: Network -> USB -> SSD. Two options to enter BIOS/UEFI:
Option 1: If your surface connect to a keyboard, repeatedly press Del key to enter bios when power on surface.
Option 2: Press and hold the volume-up button, and at the same time, press and release the power button. When the Surface logo appears, release the volume-up button, and you will see the UEFI screen in a few seconds.
2. Insert USB drive to the USB port. Note: Surface pro only support boot the OS which supports UEFI booting. So, if you create a DOS, Windows xp pe, or Windows7 pe boot disk, it will fail to boot from USB drive.
3. Press and hold the volume-down button, and then press and release the power button.
4. When the Surface logo appears, release the volume-down button. Wait for a few seconds, you will see the screen which boot from the USB drive.