diff --git a/Marlin/src/lcd/extui/dgus_e3s1pro/DGUSDisplay.cpp b/Marlin/src/lcd/extui/dgus_e3s1pro/DGUSDisplay.cpp
index b897466c6afe..571626aa77b4 100644
--- a/Marlin/src/lcd/extui/dgus_e3s1pro/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/dgus_e3s1pro/DGUSDisplay.cpp
@@ -337,8 +337,8 @@ void DGUSDisplay::processRx() {
 
 size_t DGUSDisplay::getFreeTxBuffer() {
   return (
-    #ifdef LCD_SERIAL_GET_TX_BUFFER_FREE
-      LCD_SERIAL_GET_TX_BUFFER_FREE()
+    #ifdef LCD_SERIAL_TX_BUFFER_FREE
+      LCD_SERIAL_TX_BUFFER_FREE()
     #else
       SIZE_MAX
     #endif
diff --git a/Marlin/src/lcd/extui/dgus_reloaded/DGUSDisplay.cpp b/Marlin/src/lcd/extui/dgus_reloaded/DGUSDisplay.cpp
index 31272681804f..741c36fde634 100644
--- a/Marlin/src/lcd/extui/dgus_reloaded/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/dgus_reloaded/DGUSDisplay.cpp
@@ -334,8 +334,8 @@ void DGUSDisplay::processRx() {
 
 size_t DGUSDisplay::getFreeTxBuffer() {
   return (
-    #ifdef LCD_SERIAL_GET_TX_BUFFER_FREE
-      LCD_SERIAL_GET_TX_BUFFER_FREE()
+    #ifdef LCD_SERIAL_TX_BUFFER_FREE
+      LCD_SERIAL_TX_BUFFER_FREE()
     #else
       SIZE_MAX
     #endif