diff --git a/components/free_rtos/ethernet_industry/eth_ecat_packer.hpp b/components/free_rtos/ethernet_industry/eth_ecat_packer.hpp
index cc63297..d9ad2fe 100644
--- a/components/free_rtos/ethernet_industry/eth_ecat_packer.hpp
+++ b/components/free_rtos/ethernet_industry/eth_ecat_packer.hpp
@@ -23,7 +23,7 @@ struct Padding {
 
 struct PackFunctorBase {
     uint8_t *raw;
-    bool skip;
+    const bool skip;
 
     template<typename DataT>
     void operator()(DataT& data) {