diff --git a/ffi/capi/js/examples/tinywasm/Makefile b/ffi/capi/js/examples/tinywasm/Makefile
index 1f8e2c9643f..24586e39203 100755
--- a/ffi/capi/js/examples/tinywasm/Makefile
+++ b/ffi/capi/js/examples/tinywasm/Makefile
@@ -44,7 +44,8 @@ data.postcard: icu_capi.wasm
 		--keys-for-bin icu_capi.wasm \
 		--locales full \
 		--format blob \
-		--out data.postcard
+		--out data.postcard \
+		--overwrite
 
 build: icu_capi.wasm data.postcard lib