diff --git a/src/main/drivers/bus_i2c_stm32f10x.c b/src/main/drivers/bus_i2c_stm32f10x.c
index 0849a0356..f31f05205 100644
--- a/src/main/drivers/bus_i2c_stm32f10x.c
+++ b/src/main/drivers/bus_i2c_stm32f10x.c
@@ -79,7 +79,7 @@ static void i2cUnstick(IO_t scl, IO_t sda);
 #define I2C3_SCL PA8
 #endif
 #ifndef I2C3_SDA
-#define I2C3_SDA PB4
+#define I2C3_SDA PC9
 #endif
 #endif