diff --git a/src/drivers/imu/mpu9250/mpu9250.cpp b/src/drivers/imu/mpu9250/mpu9250.cpp
index 280c1fb154..efd5670918 100644
--- a/src/drivers/imu/mpu9250/mpu9250.cpp
+++ b/src/drivers/imu/mpu9250/mpu9250.cpp
@@ -495,7 +495,7 @@ MPU9250::check_registers()
 
 	if ((v = read_reg(_checked_registers[_checked_next], MPU9250_HIGH_BUS_SPEED)) != _checked_values[_checked_next]) {
 
-		PX4_DEBUG("reg: %d = %d (should be %d) _reset_wait: %llu", _checked_registers[_checked_next], v,
+		PX4_DEBUG("reg: %d = %d (should be %d) _reset_wait: %lu", _checked_registers[_checked_next], v,
 			  _checked_values[_checked_next], _reset_wait);
 
 		/*
diff --git a/src/drivers/imu/mpu9250/mpu9250.h b/src/drivers/imu/mpu9250/mpu9250.h
index ece19ad6c3..890d3a7c8d 100644
--- a/src/drivers/imu/mpu9250/mpu9250.h
+++ b/src/drivers/imu/mpu9250/mpu9250.h
@@ -214,7 +214,7 @@ struct MPUReport {
  */
 #define MPU9250_LOW_BUS_SPEED				0
 #define MPU9250_HIGH_BUS_SPEED				0x8000
-#define MPU9250_REG_MASK					0x00FF
+#define MPU9250_REG_MASK				0x00FF
 #  define MPU9250_IS_HIGH_SPEED(r) 			((r) & MPU9250_HIGH_BUS_SPEED)
 #  define MPU9250_REG(r) 					((r) & MPU9250_REG_MASK)
 #  define MPU9250_SET_SPEED(r, s) 			((r)|(s))
diff --git a/src/drivers/imu/mpu9250/mpu9250_i2c.cpp b/src/drivers/imu/mpu9250/mpu9250_i2c.cpp
index 943684765e..5e547751e5 100644
--- a/src/drivers/imu/mpu9250/mpu9250_i2c.cpp
+++ b/src/drivers/imu/mpu9250/mpu9250_i2c.cpp
@@ -43,7 +43,7 @@
 
 #ifdef USE_I2C
 
-device::Device *MPU9250_I2C_interface(int bus, uint32_t address);
+device::Device *MPU9250_I2C_interface(int bus, uint32_t address, int bus_frequency);
 
 class MPU9250_I2C : public device::I2C
 {
@@ -55,7 +55,7 @@ public:
 	int	write(unsigned address, void *data, unsigned count) override;
 
 protected:
-	virtual int	probe();
+	virtual int	probe() override;
 
 private:
 
@@ -97,7 +97,7 @@ MPU9250_I2C::read(unsigned reg_speed, void *data, unsigned count)
 	 */
 	uint32_t offset = count < sizeof(MPUReport) ? 0 : offsetof(MPUReport, ACCEL_XOUT_H);
 	uint8_t cmd = MPU9250_REG(reg_speed);
-	return transfer(&cmd, 1, &((uint8_t *)data)[offset], count);
+	return transfer(&cmd, 1, &((uint8_t *)data)[offset], count - offset);
 }
 
 int