ReactOS Achieves ARM64 Support, Successfully Boots Windows-Compatible OS on Raspberry Pi 5

A New Milestone for the Open-Source OS

Continuing the Legacy of Windows NT The open-source project “ReactOS,” which has aimed to faithfully recreate Windows NT for over 30 years, has reached a new milestone. The team achieved support for the ARM64 architecture and released an experimental build that runs on the Raspberry Pi 5.

Background and Significance of ARM64 Port

ReactOS has traditionally operated on x86 architecture. However, in recent years, ARM-based processors have rapidly gained prominence, with the success of Apple Silicon and the expansion of ARM architecture adoption across servers and edge devices. In this context, ReactOS’s decision to support ARM64 is highly significant. Unlike WINE, which layers a Windows application compatibility layer on Linux, ReactOS reconstructs the NT kernel from scratch and strives for compatibility with Windows down to driver support. While this approach makes porting to ARM64 more complex, it also amplifies the impact of its success.

An Eight-Month Development Challenge

Achieving ARM64 support was no easy feat. ReactOS contributors reportedly spent eight months ensuring the code could run successfully. The requirements are stringent, demanding a UEFI ARM64 system with GICv2 or v3 enabled and support for ARMv8-A or later boards. The Raspberry Pi 5 was treated as a special case, and according to testing by The Register, the boot process was far from straightforward.

The Experimental Nature of the Build The

ReactOS team has clearly stated that the ARM64 build is “still in an experimental state.” Screenshots released show the OS functioning on ARM64 via QEMU and on the Raspberry Pi 5, but its capabilities remain limited at this stage. The project describes itself as an “alpha-quality operating system” and warns against using it in production environments or even for testing on devices users cannot afford to sacrifice. Criticism of its stability or application support would be premature at this point.

30 Years of History and Current Progress

ReactOS is set to celebrate the 30th anniversary of its first source tree commit in 2026. Its current development target is compatibility with Windows Server 2003, and a review of the latest builds in 2025 praised its faithful recreation of Windows’s golden era. The most recent stable release, version 0.4.15, marked the first update since 2021. The project has demonstrated progress through milestones such as showcasing SMP (Symmetric Multi-Processing) support and hiring full-time developers.

The Significance of Displaying the Desktop To

dismiss the ARM64 version of ReactOS as “just booting” would be an oversimplification. Seeing a Windows desktop appear on ARM64 hardware is a culmination of years of development effort and a moment of genuine triumph for the open-source community. However, this milestone is merely a starting point. There are still numerous challenges to overcome before ReactOS can run practical applications and provide a stable environment on ARM64 hardware. The ambition to transfer Windows NT’s legacy to next-generation architectures through open-source efforts marks a significant chapter in computing history.

Future Outlook ReactOS’s ARM64 support is

merely the beginning of a process. The goal of creating a functional Windows-compatible environment on architectures beyond x86 will grow increasingly important as computing continues to diversify. Moving beyond the experimental phase and achieving practical ARM64 compatibility will be the next major challenge for the ReactOS project. ---