Focused port of the fork's fix/setup-host-bios-deadlock feature (10 commits) onto current upstream master, per the 2026-09-10 decision to port rather than rebase (the fork line and upstream share no merge base).
Content: the codegen host accepts any recompiled BIOS stem instead of only OpenBIOS/SCPH1001 (psx_bios_known_images.h); the runtime checks the setup host before validating a chosen BIOS and the first-run loop breaker reports a cause-specific reason; the CLI decodes subprocess output as UTF-8; --setup-selfcheck verifies a headless setup; the rbengine preflight names the recursive init. Two port conflicts resolved: the new CTest registrations in recompiler/CMakeLists.txt are kept (the names exist only in this change), and runtime.cmake takes the new recomp-ui guidance text. Cubic P3 finding fixed: the sibling PSX_NETPLAY FATAL_ERROR now also names --recursive.
Evidence: python syntax checks pass for psxrecomp_cli.py and the new tests; runtime/tests/test_codegen_host_bios_stems.py runs or skips only on a missing RECOMP_UI_ROOT. No full runtime build or retail route is claimed here. Developed with AI assistance (Cline, 2026-09-10).
Matthew Stanley