It was my impression that Windows had a requirement on UEFI to boot on ARM? Or is that not true?
In fact, my current ASUS laptop did not allow me to install Windows until I have performed a sophisticated dance to update/flash some sort of low-level disk-related Intel bloatware. The laptop was sold without OS and was accompanied by a small paper referencing a website with instruction how to flash the firmware to actually make the laptop usable.