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Cordial runs Roblox’s Android build natively: it loads the engine built for the host’s own architecture and never translates machine code. There is no translation layer, and none is planned (ADR-043). The architecture is fixed when Cordial is built, so a Cordial built for aarch64 installs and runs the aarch64 build of Roblox. Settings shows it in a read-only Roblox build row; there is no dropdown, because choosing the other architecture’s build would change nothing Cordial can run. Builds are kept in ~/.local/share/cordial/builds/<version>, which is not keyed by architecture: two architectures sharing one home directory and one version number would meet in one directory. Cordial refuses a build whose engine differs from the one kept under that version, by name, rather than overwriting it (INFERRED for two architectures; not tried).

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aarch64

What has been checked. The code builds for aarch64, and the packaging, release and CI jobs have aarch64 legs. A real, Roblox-signed arm64-v8a libroblox.so was fetched through Cordial’s own mirror path, its signature verified, and loaded under qemu-user emulation (4K pages) in a one-off session: cordial-run got through the bionic linker, JNI_OnLoad, GameActivity native init and the engine’s own flag initialisation (139 flags) before the time bound ended, with no crash and no undefined symbol. No command line for that session was kept, so it cannot be repeated from here. What has not.
  • Anything on real ARM64 hardware. Emulation says nothing about 16K-page machines.
  • 16K-page kernels. Asahi on Apple silicon is 16K, and recent Raspberry Pi OS defaults the Pi 5 to a 16K kernel; most postmarketOS phone SoCs and Graviton are 4K. On 16K the linker maps the engine read-write-execute and never re-protects it, which bypasses the patch that makes the engine’s text read-only (ADR-001). Android 15 also requires 16 KB aligned libraries, so an arm64-v8a build may take that path even on a 4K host. A 4K aarch64 host is plausibly a mechanical job; a 16K one is not.
  • The arm64-v8a engine’s DT_TEXTREL and p_align. The readelf check has not been run against that binary.

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Known gaps

  • A Roblox version released only for ARM64 is not shown on x86_64 machines, and on an aarch64 machine an ARM-only release newer than the current x86_64 one does not show as the newest. The mirror is queried for the x86_64 bundle shape on both architectures. Fixing it needs XAPK split-bundle support in the updater.
  • Arch is x86-64 only. Arch Linux does not build for aarch64.

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VR is the one translated build

The Meta Quest build ships only arm64-v8a. The VR mode runs its engine under an in-process translator (dynarmic) inside the x86-64 cordial-run, with the host’s own Vulkan driver and OpenXR runtime (ADR-053, VR). It is stored apart under builds/arm64-v8a/. It has been measured on Monado’s simulated headset only: 90 frames/s at 90 Hz on the landing panel, 44 to 65 in game. Nothing has been measured on WiVRn or a real headset.