Developer-friendly OEMs like OnePlus and Sony are known for publishing kernel sources as well as device trees; the latter serves as a mechanism to describe the hardware to the Linux-based kernel of Android on ARM platform as soon as the primary bootloader boots. Operating systems like Microsoft Windows, however, utilize the Advanced Configuration and Power Interface (ACPI) for the same task, while the low level hardware initialization is handled by the Unified Extensible Firmware Interface (UEFI) nowadays. Interestingly, it is possible to port UEFI and ACPI support to existing ARM devices with ample hacking, thus you can technically boot Windows 10 on devices like the Raspberry Pi.
Windows 10 does natively support the ARM architecture, which is indeed a plus in this porting game. A developer known as Evsio0n has now published a proof-of-concept method to boot Windows 10 on ARM on the Qualcomm Snapdragon 835-powered Samsung Galaxy S8. This is not the first time we have seen Windows 10 up and running on Android phones, but Evsio0n has also shared the source code to build the barebone UEFI firmware for the Galaxy S8 based on the TianoCore project.
At the time of reporting, the firmware is capable of booting Windows Preinstallation Environment (AKA WinPE), but the lack of complete ACPI implementation prohibits full-blown Windows 10 to be booted. The memory management unit (MMU) is working to some extent, which is enough for Debian Linux with mainline Linux 5.x kernel to boot.
Evsio0n has credited Bingxing Wang, AKA imbushuo, and fxsheep for their contributions in this field. Another tinkerer named Tom Christopher Daniel Perez did tease (but later deleted) a similar development on the Xiaomi Mi 6 (probably based on fxsheep's existing UEFI port for the device), which indicates that other Snapdragon 835-powered phones could eventually be supported by the project. While the current port is far from being a daily driver, especially when compared to the Lumia WOA project, Windows 10 might be useful to significantly extend the lifetime of these legacy flagships.