for Intel/AMD PCs, the ARM situation is fundamentally different. No Public ISOs
: Reliable copies of official ISOs, such as Windows 8.1 English x64 , are often hosted on the Internet Archive for preservation. windows 81 arm64 iso install
Historically, Windows 8.1 was never released as a "64-bit ARM" (ARM64) operating system for consumers. Windows RT 8.1 (The Official Version): This was a 32-bit (ARM32) OS. It came pre-installed on devices like the Surface RT for Intel/AMD PCs, the ARM situation is fundamentally
: Standard UEFI bootloaders often reject these unsigned or experimental builds, requiring tools like TianoCore or specific modifications to bypass Secure Boot. Windows RT 8
This is an experimental, community-driven process. It is a true install—it involves extracting ARM32 system files and running them under emulation or hacking the UEFI of a Qualcomm device. Warning: You will likely brick your device or lose functionality (Wi-Fi, touch, storage drivers).
Crucially, ARM64 support for Windows didn't mature until the later builds of Windows 10. Consequently, there is no official ISO available from Microsoft for this specific configuration. Any existing "Windows 8.1 ARM64" project typically involves complex "backporting" or the use of leaked engineering builds that were never intended for public use. The Installation Challenge