ISA Matters: Valve developers have been working hard to finalize the software stack for the upcoming Steam Frame. Despite using an Arm-based processor, the VR headset is expected to support both PC and Android games thanks to a complex compatibility layer.
Valve recently updated the Steam pages for Lepton and FEX, two tools designed to improve compatibility between the popular PC gaming platform and Arm-based devices. The tools are expected to play a major role in turning the upcoming Steam Frame into a "real" gaming headset from the get-go.
Lepton and FEX still lack public store pages on Steam, but their update histories can be viewed through SteamDB's archive. The first hints about Lepton appeared online in 2025, suggesting that Valve was embarking on yet another major compatibility project. Just as Proton acts as a compatibility layer for Windows games on Linux using Wine, Lepton is expected to leverage the container-based Waydroid system to run Android apps on a full Linux distribution.
– Brad Lynch (@SadlyItsBradley) August 1, 2026
Meanwhile, FEX is an emulator designed to translate API calls and recompile code from x86 applications into native implementations for the Arm64 instruction set architecture (ISA). The emulator is designed to reduce emulation overhead and improve performance, and it can already offer "broad" compatibility with both 32-bit and 64-bit x86 binary applications – i.e., games.
FEX was previously advertised as a compatibility tool that could be used alongside Wine/Proton to play Windows games on Arm devices. With Valve taking part in the project, the emulator could quickly gain traction, just as Proton has become a major player and software product in the Linux gaming market.
Lepton, Proton, and FEX are expected to handle game compatibility within the Steam Frame ecosystem. The upcoming VR headset is based on a Snapdragon 8 Gen 3 Arm64 SoC and a SteamOS build based on the Arch Linux distribution. Valve is also known for providing financial support to the Arch project.
Steam Frame's compatibility setup should work something like this: Lepton will handle Android games in its container-based system, while FEX will translate x86-64 native code to Arm. Finally, Proton will run Windows-based software on the Arm architecture.
Earlier this year, Valve announced that the headset's final release date had been delayed due to the memory shortage crisis caused by AI data center overprovisioning. Now that two major pieces of the device's software stack are finally showing their "faces" in public, the actual launch date for Steam Frame should not be too far away.