diff --git a/nuttx-configs/auav-x21/include/board.h b/nuttx-configs/auav-x21/include/board.h
index c5ba583ac6a8..215f5e8fa132 100755
--- a/nuttx-configs/auav-x21/include/board.h
+++ b/nuttx-configs/auav-x21/include/board.h
@@ -261,6 +261,10 @@
 #define GPIO_I2C1_SDA		GPIO_I2C1_SDA_2
 #define GPIO_I2C1_SCL_GPIO	(GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN8)
 #define GPIO_I2C1_SDA_GPIO	(GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN9)
+#define GPIO_I2C2_SCL    GPIO_I2C2_SCL_1
+#define GPIO_I2C2_SDA    GPIO_I2C2_SDA_1
+#define GPIO_I2C2_SCL_GPIO  (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN10)
+#define GPIO_I2C2_SDA_GPIO  (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN11)
 
 /*
  * SPI
diff --git a/nuttx-configs/auav-x21/nsh/defconfig b/nuttx-configs/auav-x21/nsh/defconfig
index db2bd5d314b8..010de67c5f6b 100644
--- a/nuttx-configs/auav-x21/nsh/defconfig
+++ b/nuttx-configs/auav-x21/nsh/defconfig
@@ -423,7 +423,7 @@ CONFIG_STM32_DMA2=y
 # CONFIG_STM32_FSMC is not set
 # CONFIG_STM32_HASH is not set
 CONFIG_STM32_I2C1=y
-# CONFIG_STM32_I2C2 is not set
+CONFIG_STM32_I2C2=y
 # CONFIG_STM32_I2C3 is not set
 # CONFIG_STM32_OPAMP is not set
 CONFIG_STM32_OTGFS=y
diff --git a/src/drivers/boards/auav-x21/board_config.h b/src/drivers/boards/auav-x21/board_config.h
index e10976462b9e..56f8f90f8af1 100644
--- a/src/drivers/boards/auav-x21/board_config.h
+++ b/src/drivers/boards/auav-x21/board_config.h
@@ -109,9 +109,10 @@
 
 /* I2C busses */
 
-/* There is no I2C2 so there is not notion of internal / external*/
-#define PX4_I2C_BUS_EXPANSION 1
-#define PX4_I2C_BUS_LED		PX4_I2C_BUS_EXPANSION
+/* I2C busses */
+#define PX4_I2C_BUS_EXPANSION 	1
+#define PX4_I2C_BUS_ONBOARD	2
+#define PX4_I2C_BUS_LED		PX4_I2C_BUS_ONBOARD
 
 /* Devices not on the onboard bus.
  *