diff --git a/src/runtime-rs/Makefile b/src/runtime-rs/Makefile
index 34fa7ab598..0bb0617ff9 100644
--- a/src/runtime-rs/Makefile
+++ b/src/runtime-rs/Makefile
@@ -580,7 +580,7 @@ static-checks-build: $(GENERATED_FILES)
 $(TARGET): $(GENERATED_FILES) $(TARGET_PATH)
 
 $(TARGET_PATH): $(SOURCES) | show-summary
-	@RUSTFLAGS="$(EXTRA_RUSTFLAGS) --deny warnings" cargo build --target $(TRIPLE) --$(BUILD_TYPE) $(EXTRA_RUSTFEATURES)
+	@RUSTFLAGS="$(EXTRA_RUSTFLAGS) --deny warnings" cargo build --target $(TRIPLE) $(if $(findstring release,$(BUILD_TYPE)),--release) $(EXTRA_RUSTFEATURES)
 
 $(GENERATED_FILES): %: %.in
 	@sed \