diff --git a/src/modules/SX128x/SX128x.cpp b/src/modules/SX128x/SX128x.cpp
index 25ac0a43..58ba3b29 100644
--- a/src/modules/SX128x/SX128x.cpp
+++ b/src/modules/SX128x/SX128x.cpp
@@ -964,7 +964,7 @@ int16_t SX128x::setDataShaping(uint8_t sh) {
   }
 }
 
-int16_t SX128x::setSyncWord(uint8_t* syncWord, uint8_t len) {
+int16_t SX128x::setSyncWord(const uint8_t* syncWord, uint8_t len) {
   // check active modem
   uint8_t modem = getPacketType();
   if(!((modem == RADIOLIB_SX128X_PACKET_TYPE_GFSK) || (modem == RADIOLIB_SX128X_PACKET_TYPE_FLRC))) {
diff --git a/src/modules/SX128x/SX128x.h b/src/modules/SX128x/SX128x.h
index fd8e2e03..782b95cd 100644
--- a/src/modules/SX128x/SX128x.h
+++ b/src/modules/SX128x/SX128x.h
@@ -666,7 +666,7 @@ class SX128x: public PhysicalLayer {
       \param len Sync word length in bytes.
       \returns \ref status_codes
     */
-    int16_t setSyncWord(uint8_t* syncWord, uint8_t len);
+    int16_t setSyncWord(const uint8_t* syncWord, uint8_t len);
 
     /*!
       \brief Sets LoRa sync word.