diff --git a/libraries/AP_HAL_ChibiOS/hwdef/MambaH743v4/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/MambaH743v4/hwdef.dat
index 942924ad471a7..2d35285e58f5f 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/MambaH743v4/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/MambaH743v4/hwdef.dat
@@ -101,17 +101,18 @@ define HAL_GPIO_B_LED_PIN 90
 PA9  USART1_TX USART1
 PA10 USART1_RX USART1
 
-# USART2
-PD5 USART2_TX USART2 NODMA
-PD6 USART2_RX USART2 NODMA
+# USART2 (GPS)
+PD5 USART2_TX USART2
+PD6 USART2_RX USART2
+define DEFAULT_SERIAL2_PROTOCOL SerialProtocol_GPS
 
 # USART3 (VTX)
 PD8 USART3_TX USART3 NODMA
 PD9 USART3_RX USART3 NODMA
 
-# UART4 (GPS)
-PD1 UART4_TX UART4
-PD0 UART4_RX UART4
+# UART4 (WiFi)
+PD1 UART4_TX UART4 NODMA
+PD0 UART4_RX UART4 NODMA
 
 # UART5 (SPORT)
 PC12 UART5_TX UART5 NODMA