diff --git a/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
index eea0b4785433c..4a9e82c69a9b4 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
@@ -74,8 +74,11 @@ SERIAL_ORDER OTG1 USART6 USART1 UART4 UART5 USART3
 PB11 TIM2_CH4 TIM2 RCININT PULLDOWN LOW
 PB10 USART3_TX USART3
 
+# alternative
+PB11 USART3_RX USART3 ALT(1)
+
 # SBUS inversion control pin, active high
-PB15 USART3_RXINV OUTPUT LOW GPIO(78) POL(1)
+PB15 USART3_RXINV OUTPUT LOW GPIO(78) POL(0)
 
 # for FrSky S.PORT. Has builtin inverters and diode to combine
 # RX and TX onto the one pin