It is impossible to provide a legitimate, direct download link for a Windows 8.1 ARM64 ISO because
Insert the USB into your target machine, restart, and enter the BIOS/boot menu to boot from the USB drive.
Standard flashing tools like Rufus often fail with ARM64 ISOs intended for development builds. The most reliable method is using native Windows deployment tools (DISM) via the command line. Requirements: A host PC running Windows 10 or 11. A USB 3.0 flash drive (16GB minimum).
Disclaimer: As of 2026, official ARM64 support for Windows 8.1 does not exist, and Microsoft's official ARM journey began with Windows 10/11. The information below clarifies the limitations and discusses the closest alternatives. Understanding the Landscape: Windows 8.1 and ARM windows 81 arm64 iso install
Note: This is only applicable when you have an OEM recovery image intended for the exact hardware model.
There’s no official link. The only surviving Arm64 builds of Windows 8.1 come from:
However, Windows RT 8.1 remains trapped in the past, with limited application support and no official emulation layer for x86 programs. As a result, installing Windows 8.1 on modern ARM devices, such as the Raspberry Pi, is not officially supported by either Microsoft or the Raspberry Pi Foundation [2†L7-L8】. It is impossible to provide a legitimate, direct
Place the UEFI files into the FAT32 EFI partition you created.
While there is no official ISO, the modding community managed to create custom "flatlines" or WIM images of Windows RT 8.1 that can be applied to hardware if the Secure Boot chain is broken.
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 Requirements: A host PC running Windows 10 or 11
What are you trying to install this on?
You cannot use standard Windows installation prompts. You must manually partition your target storage drive using diskpart on your host PC. Open Command Prompt as Administrator and type diskpart . Type list disk to find your SD card or USB drive. Clean the disk and convert it to GPT.
Microsoft never publicly released a retail ISO for Windows 8.1 ARM64. However, internal development builds and compiled project files leaked over the years, giving the hobbyist community the foundation needed to build custom installation images.