This article describes three ways to bypass the Windows boot order by booting your Surface Pro from a USB drive. Booting your Surface Pro from a USB drive can be used to upgrade to a new version of Windows if the standard Windows installer fails; it is also necessary to downgrade from a more recent version of Windows or install an alternative operating system.
How to boot a Surface from a USB device | Microsoft
The steps below will boot your Surface Pro (or other Surface device) from a bootable USB flash drive.
Turn off your Surface Pro if it's on, in sleep, or in hibernation mode.
Connect the bootable USB drive to a USB port.
