diff --git a/src/main/drivers/uart_inverter.c b/src/main/drivers/uart_inverter.c
index b815883df79..5168831b471 100644
--- a/src/main/drivers/uart_inverter.c
+++ b/src/main/drivers/uart_inverter.c
@@ -145,7 +145,12 @@ void uartInverterSet(USART_TypeDef *USARTx, uartInverterLine_e line, bool enable
 
 // UART4
 #if defined(INVERTER_PIN_UART4_RX) || defined(INVERTER_PIN_UART4_TX)
-    if (USARTx == USART4) {
+#if defined(STM32F4)
+    if (USARTx == UART4)
+#else
+    if (USARTx == USART4)
+#endif
+    {
 #if defined(INVERTER_PIN_UART4_RX)
         rx_pin = IOGetByTag(IO_TAG(INVERTER_PIN_UART4_RX));
 #endif
diff --git a/src/main/target/TUNERCF405/target.h b/src/main/target/TUNERCF405/target.h
index f193377c6ea..b359545e697 100644
--- a/src/main/target/TUNERCF405/target.h
+++ b/src/main/target/TUNERCF405/target.h
@@ -103,6 +103,8 @@
 #define USE_UART4
 #define UART4_RX_PIN            PA1
 #define UART4_TX_PIN            PA0
+#define USE_UART_INVERTER
+#define INVERTER_PIN_UART4_RX   PC14
 
 #define USE_UART5
 #define UART5_RX_PIN            PD2