diff --git a/libraries/AP_HAL_ChibiOS/hwdef/omnibusf4pro/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/omnibusf4pro/hwdef.dat
index 052a5d2550..dae30993fd 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/omnibusf4pro/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/omnibusf4pro/hwdef.dat
@@ -46,8 +46,9 @@ PA5 SPI1_SCK SPI1
 PA6 SPI1_MISO SPI1
 PA7 SPI1_MOSI SPI1
 
-PB10 I2C2_SCL I2C2
-PB11 I2C2_SDA I2C2
+# note that this board needs PULLUP on I2C pins
+PB10 I2C2_SCL I2C2 PULLUP
+PB11 I2C2_SDA I2C2 PULLUP
 
 PB15 SPI2_MOSI SPI2
 PB14 SPI2_MISO SPI2