diff --git a/libraries/AP_HAL_ChibiOS/hwdef/OMNIBUSF7V2/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/OMNIBUSF7V2/hwdef.dat
index 9ad669de29..0c6489e57e 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/OMNIBUSF7V2/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/OMNIBUSF7V2/hwdef.dat
@@ -59,7 +59,7 @@ PE2 SPI4_SCK SPI4
 PE5 SPI4_MISO SPI4
 PE6 SPI4_MOSI SPI4
 
-# optional I2C device2, shared with USART3
+# external I2C device2, pins shared with USART3, normally disabled
 PB10 I2C2_SCL I2C2
 PB11 I2C2_SDA I2C2
 
@@ -87,9 +87,9 @@ PA3 TIM9_CH2 TIM9 RCININT PULLDOWN
 # alternative RC input using USART2
 PA3 USART2_RX USART2 NODMA ALT(1)
 
-# USART3
-PD9 USART3_RX USART3
-PD8 USART3_TX USART3
+# USART3, enabled as ALT config in place of I2C
+PB10 USART3_TX USART3 ALT(1)
+PB11 USART3_RX USART3 ALT(1)
 
 # USART6
 PC7 USART6_RX USART6