I think it's something else. One cannot simply shut down a Windows 8+ computer any more in order to access the boot device priority. There is a menu entry for shut down, but it's mislabelled and instead it will hibernate. This is very perplexing if one is used to how it was done before. The real working procedure is orders of magnitude more complicated and documented at https://www.tenforums.com/tutorials/5831-boot-uefi-firmware-...