diff --git a/scripts/common/apply-finalize.sh b/scripts/common/apply-finalize.sh
index 1f778c5..d4e8585 100755
--- a/scripts/common/apply-finalize.sh
+++ b/scripts/common/apply-finalize.sh
@@ -13,6 +13,12 @@ PROJECT_ROOT="$(cd "${SCRIPT_DIR}/../.." && pwd)"
 WASM_OPT=$("${SCRIPT_DIR}/get-wasm-opt.sh")
 BINARYEN_BIN=$(dirname "${WASM_OPT}")
 FINALIZE="${BINARYEN_BIN}/wasm-emscripten-finalize"
+# Same stub hazard as wasm-opt (see get-wasm-opt.sh): a host-mode kicad build
+# leaves the emsdk finalize stubbed with the real binary at .real — prefer it,
+# the stub exits 0 having done nothing.
+if [ -x "${FINALIZE}.real" ]; then
+    FINALIZE="${FINALIZE}.real"
+fi
 
 INPUT_WASM="${1:-output/pcbnew.wasm}"
 OUTPUT_WASM="${2:-${INPUT_WASM}}"
diff --git a/scripts/common/get-wasm-opt.sh b/scripts/common/get-wasm-opt.sh
index 1e9e9f7..6b33b3a 100755
--- a/scripts/common/get-wasm-opt.sh
+++ b/scripts/common/get-wasm-opt.sh
@@ -25,6 +25,15 @@ PROJECT_ROOT="$(cd "${SCRIPT_DIR}/../.." && pwd)"
 # v130 (see docs/ci-build-slowness-findings.md). Validate any bump with the e2e
 # suite: a Binaryen/emsdk skew can corrupt asyncify metadata ("func is not a function").
 EMSDK_WASM_OPT="${PROJECT_ROOT}/tools/emsdk/upstream/bin/wasm-opt"
+# build-kicad-target.sh replaces emsdk's wasm-opt with a no-op stub (moving the
+# real binary to wasm-opt.real) so emcc skips the in-link asyncify. That's meant
+# for the container emsdk, but a host-mode run leaves the HOST emsdk stubbed —
+# and the stub fakes --version and exits 0, so the host-side asyncify/-O2
+# "succeed" while doing NOTHING (broken wasm: "asyncify_stop_unwind is not a
+# function"). Always prefer the preserved real binary when it exists.
+if [ -x "${EMSDK_WASM_OPT}.real" ]; then
+    EMSDK_WASM_OPT="${EMSDK_WASM_OPT}.real"
+fi
 if [ -z "${BINARYEN_VERSION:-}" ] && [ -x "${EMSDK_WASM_OPT}" ]; then
     EMSDK_VERSION=$("${EMSDK_WASM_OPT}" --version 2>&1 || true)
     echo "Using emsdk-bundled Binaryen: ${EMSDK_VERSION}" >&2