32-bit ARM (armeabi-v7a) libraries run inside a normal 64-bit Android app on the
Steam Frame, without Android's native-bridge mechanism (no Lepton changes): each
libX.so becomes libX.a32.so plus a 64-bit stub, next to liba32bridge.so (the
translator + host glue) and liba32rt.so (a 32-bit static-PIE runtime with bionic's
libc/libm/libz/libstdc++ and a loader for the game's libraries). Guest and host
talk through hypercalls (SVC 0, r7 = 0x0a32xxxx).
Bridge (native/a32translator/bridge):
- JNI both ways: generated + hand-written JNIEnv/JavaVM, RegisterNatives and
Java_* exports through AAPCS64 -> AAPCS32 trampolines, handles for references,
arrays/strings shared when below 4 GiB, else copied
- NativeActivity glue, libandroid imports (weak, generated from imports.txt)
- GLES 3.2 + extensions + EGL: 996 functions generated from the NDK headers
- OpenSL ES output implemented in the guest, played through AAudio
- VrApi 1.x (Gear VR era) translated to the 64-bit VrApi -> OpenXR bridge,
including OVRPlugin 1.12's frame layout and its wrapped (app texture) chains
- controller input as Gear VR touchpad/back/gamepad events (UnityPlayer.injectEvent)
- convert.py: prototype of the APK conversion (FramePort patch to follow)
- PC harness with a fake JVM (32 checks, qemu or native) and an on-device test APK
Translator fixes found on the way: guest signals during blocking system calls
and in host code (Boehm GC deadlock in Unity's Mono), static-PIE start files and
PT_TLS/PT_GNU_RELRO bias, host fault chaining, stderr to logcat in bridge mode.
vrapi-bridge: OVP_HEADLESS_TEST=1 skips the wait for a tracked head (automated
tests without a worn headset); upstream-patches/runtime.cpp.patch updated.
Verified on the Frame (2026-10-10): AFFECTED The Manor (Unity 5.6 + Mono,
OVRPlugin 1.12) runs in the headset with picture and sound; controls in progress.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
