diff --git a/scripts/build-android.sh b/scripts/build-android.sh
index 8cf1345..297bb1d 100755
--- a/scripts/build-android.sh
+++ b/scripts/build-android.sh
@@ -49,6 +49,9 @@ ABIS="${ABIS:-arm64-v8a}"
 # Expo both do that, and so does the gomobile binding layer. The build still succeeds; the app crashes
 # on the device. This cannot be verified by looking at a file size, and it must not become the default
 # until a build with it has been opened on a real phone, connected to a tailnet, and used.
+# Expanded below as ${MINIFY_ARGS[@]+...} rather than bare: macOS ships bash 3.2, where expanding an
+# EMPTY array under `set -u` is itself an unbound-variable error. The monorepo's copy of this script
+# survives the bare form only because it does not set -u — the bug was latent there and real here.
 MINIFY_ARGS=()
 if [[ "${MINIFY:-0}" == "1" ]]; then
 	MINIFY_ARGS=(-Pandroid.enableMinifyInReleaseBuilds=true)
@@ -57,7 +60,7 @@ fi
 # assembleRelease, always. A debug build needs Metro attached and behaves differently from what ships,
 # so testing it answers the wrong question.
 if ! (cd android && ./gradlew :app:assembleRelease -PreactNativeArchitectures="$ABIS" \
-	"${MINIFY_ARGS[@]}" --console=plain) >>"$log" 2>&1; then
+	${MINIFY_ARGS[@]+"${MINIFY_ARGS[@]}"} --console=plain) >>"$log" 2>&1; then
 	echo "GRADLE FAILED — $log"; exit 1
 fi