diff --git a/tools/copy-libs.sh b/tools/copy-libs.sh
index 76457e8ee..b0b7bb190 100755
--- a/tools/copy-libs.sh
+++ b/tools/copy-libs.sh
@@ -63,7 +63,7 @@ LD_LIBS_SEARCH=""
 LD_SCRIPTS=""
 LD_SCRIPT_DIRS=""
 
-PIO_CC_FLAGS=""
+PIO_CC_FLAGS="-flto=auto "
 PIO_C_FLAGS=""
 PIO_CXX_FLAGS="-flto=auto "
 PIO_AS_FLAGS=""