diff --git a/boards/av/x-v1/src/board_config.h b/boards/av/x-v1/src/board_config.h
index 66fbae4ae8f..f56f6bd9049 100644
--- a/boards/av/x-v1/src/board_config.h
+++ b/boards/av/x-v1/src/board_config.h
@@ -266,6 +266,8 @@
 #define HRT_TIMER		     5  /* use timer5 for the HRT */
 #define HRT_TIMER_CHANNEL    1  /* use capture/compare channel 3 */
 
+/* RC Serial port */
+
 #define RC_UXART_BASE                      STM32_UART5_BASE
 #define RC_SERIAL_PORT                     "/dev/ttyS4"
 #define BOARD_HAS_SINGLE_WIRE              0 /* HW is capable of Single Wire */
@@ -367,16 +369,6 @@ int stm32_sdio_initialize(void);
 
 extern void stm32_spiinitialize(void);
 
-/************************************************************************************
- * Name: stm32_spi_bus_initialize
- *
- * Description:
- *   Called to configure SPI Buses.
- *
- ************************************************************************************/
-
-extern int stm32_spi_bus_initialize(void);
-
 void board_spi_reset(int ms);
 #define board_peripheral_reset(ms)
 
diff --git a/boards/px4/fmu-v2/src/board_config.h b/boards/px4/fmu-v2/src/board_config.h
index 0fdf8d2fe1c..e2a4547dff8 100644
--- a/boards/px4/fmu-v2/src/board_config.h
+++ b/boards/px4/fmu-v2/src/board_config.h
@@ -494,16 +494,6 @@ __BEGIN_DECLS
 
 extern void stm32_spiinitialize(void);
 
-/************************************************************************************
- * Name: stm32_spi_bus_initialize
- *
- * Description:
- *   Called to configure SPI Buses.
- *
- ************************************************************************************/
-
-extern int stm32_spi_bus_initialize(void);
-
 /****************************************************************************************************
  * Name: board_spi_reset board_peripheral_reset
  *
diff --git a/boards/px4/fmu-v3/src/board_config.h b/boards/px4/fmu-v3/src/board_config.h
index 0fdf8d2fe1c..4d305940d8e 100644
--- a/boards/px4/fmu-v3/src/board_config.h
+++ b/boards/px4/fmu-v3/src/board_config.h
@@ -494,15 +494,6 @@ __BEGIN_DECLS
 
 extern void stm32_spiinitialize(void);
 
-/************************************************************************************
- * Name: stm32_spi_bus_initialize
- *
- * Description:
- *   Called to configure SPI Buses.
- *
- ************************************************************************************/
-
-extern int stm32_spi_bus_initialize(void);
 
 /****************************************************************************************************
  * Name: board_spi_reset board_peripheral_reset
diff --git a/boards/px4/fmu-v4/src/board_config.h b/boards/px4/fmu-v4/src/board_config.h
index 957ea156856..c712feb2628 100644
--- a/boards/px4/fmu-v4/src/board_config.h
+++ b/boards/px4/fmu-v4/src/board_config.h
@@ -290,6 +290,8 @@
 #define HRT_PPM_CHANNEL              3  /* use capture/compare channel 3 */
 #define GPIO_PPM_IN                  (GPIO_ALT|GPIO_AF2|GPIO_PULLUP|GPIO_PORTB|GPIO_PIN0)
 
+/* RC Serial port */
+
 #define RC_SERIAL_PORT               "/dev/ttyS4"
 
 /* PWM input driver. Use FMU AUX5 pins attached to timer4 channel 2. */
diff --git a/boards/px4/fmu-v5/src/board_config.h b/boards/px4/fmu-v5/src/board_config.h
index 9249b002bfb..18c7bca7821 100644
--- a/boards/px4/fmu-v5/src/board_config.h
+++ b/boards/px4/fmu-v5/src/board_config.h
@@ -494,6 +494,8 @@
 #define HRT_PPM_CHANNEL         /* T8C1 */  1  /* use capture/compare channel 1 */
 #define GPIO_PPM_IN             /* PI5 T8C1 */ GPIO_TIM8_CH1IN_2
 
+/* RC Serial port */
+
 #define RC_UXART_BASE                      STM32_USART6_BASE
 #define RC_SERIAL_PORT                     "/dev/ttyS4"
 #define BOARD_HAS_SINGLE_WIRE              1 /* HW is capable of Single Wire */