diff --git a/src/drivers/mpu6000/mpu6000.cpp b/src/drivers/mpu6000/mpu6000.cpp
index 6f76dc4b2d..edf0ce5dea 100644
--- a/src/drivers/mpu6000/mpu6000.cpp
+++ b/src/drivers/mpu6000/mpu6000.cpp
@@ -377,7 +377,7 @@ private:
 	bool			is_external()
 	{
 		unsigned dummy;
-		return !_interface->ioctl(ACCELIOCGEXTERNAL, dummy);
+		return _interface->ioctl(ACCELIOCGEXTERNAL, dummy);
 	}
 
 	/**
diff --git a/src/drivers/mpu9250/mpu9250.h b/src/drivers/mpu9250/mpu9250.h
index 82d3fbf093..564a2c3bf8 100644
--- a/src/drivers/mpu9250/mpu9250.h
+++ b/src/drivers/mpu9250/mpu9250.h
@@ -482,7 +482,7 @@ private:
 	bool			is_external()
 	{
 		unsigned dummy;
-		return !_interface->ioctl(ACCELIOCGEXTERNAL, dummy);
+		return _interface->ioctl(ACCELIOCGEXTERNAL, dummy);
 	}
 
 	/**