diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
index ee33a2e19e..851e8b3406 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
@@ -177,10 +177,8 @@ void AP_InertialSensor_BMI160::start()
 
     _dev->get_semaphore()->give();
 
-    _accel_instance = _imu.register_accel(BMI160_ODR_TO_HZ(BMI160_ODR),
-                                          _dev->get_bus_id());
-    _gyro_instance = _imu.register_gyro(BMI160_ODR_TO_HZ(BMI160_ODR),
-                                        _dev->get_bus_id());
+    _accel_instance = _imu.register_accel(BMI160_ODR_TO_HZ(BMI160_ODR), _dev->get_bus_id_devtype(DEVTYPE_BMI160));
+    _gyro_instance = _imu.register_gyro(BMI160_ODR_TO_HZ(BMI160_ODR),   _dev->get_bus_id_devtype(DEVTYPE_BMI160));
 
     /* Call _poll_data() at 1kHz */
     _dev->register_periodic_callback(1000,
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_Backend.h b/libraries/AP_InertialSensor/AP_InertialSensor_Backend.h
index 44afdeb2f7..0bb6e1ecb4 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_Backend.h
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_Backend.h
@@ -70,6 +70,26 @@ public:
      */
     int16_t get_id() const { return _id; }
 
+    /*
+      device driver IDs. These are used to fill in the devtype field
+      of the device ID, which shows up as INS*ID* parameters to
+      users. The values are chosen for compatibility with existing PX4
+      drivers.
+      If a change is made to a driver that would make existing
+      calibration values invalid then this number must be changed.
+     */
+    enum DevTypes {
+        DEVTYPE_BMI160       = 0x09,
+        DEVTYPE_L3G4200D     = 0x10,
+        DEVTYPE_ACC_LSM303D  = 0x11,
+        DEVTYPE_ACC_BMA180   = 0x12,
+        DEVTYPE_ACC_MPU6000  = 0x13,
+        DEVTYPE_ACC_MPU9250  = 0x16,
+        DEVTYPE_GYR_MPU6000  = 0x21,
+        DEVTYPE_GYR_L3GD20   = 0x22,
+        DEVTYPE_GYR_MPU9250  = 0x24
+    };
+        
 protected:
     // access to frontend
     AP_InertialSensor &_imu;
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_L3G4200D.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_L3G4200D.cpp
index 4b76c83902..82948b7b5c 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_L3G4200D.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_L3G4200D.cpp
@@ -204,8 +204,8 @@ bool AP_InertialSensor_L3G4200D::_init_sensor(void)
  */
 void AP_InertialSensor_L3G4200D::start(void)
 {
-    _gyro_instance = _imu.register_gyro(800, _dev->get_bus_id());
-    _accel_instance = _imu.register_accel(800, _dev->get_bus_id());
+    _gyro_instance = _imu.register_gyro(800, _dev->get_bus_id_devtype(DEVTYPE_L3G4200D));
+    _accel_instance = _imu.register_accel(800, _dev->get_bus_id_devtype(DEVTYPE_L3G4200D));
 
     // start the timer process to read samples
     _dev->register_periodic_callback(1250, FUNCTOR_BIND_MEMBER(&AP_InertialSensor_L3G4200D::_accumulate, bool));
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_LSM9DS0.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_LSM9DS0.cpp
index 3bd5302f0a..407f7b225d 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_LSM9DS0.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_LSM9DS0.cpp
@@ -505,8 +505,8 @@ fail_whoami:
  */
 void AP_InertialSensor_LSM9DS0::start(void)
 {
-    _gyro_instance = _imu.register_gyro(760, _dev_gyro->get_bus_id());
-    _accel_instance = _imu.register_accel(800, _dev_accel->get_bus_id());
+    _gyro_instance = _imu.register_gyro(760, _dev_gyro->get_bus_id_devtype(DEVTYPE_GYR_L3GD20));
+    _accel_instance = _imu.register_accel(800, _dev_accel->get_bus_id_devtype(DEVTYPE_ACC_LSM303D));
 
     set_gyro_orientation(_gyro_instance, _rotation);
     set_accel_orientation(_accel_instance, _rotation);
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp
index d156bbb12a..22ae20d162 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp
@@ -210,9 +210,6 @@ extern const AP_HAL::HAL& hal;
 #endif
 #define MAX_DATA_READ (MPU6000_MAX_FIFO_SAMPLES * MPU6000_SAMPLE_SIZE)
 
-#define MPU6000_DRIVER_VERSION_ACCEL 1U
-#define MPU6000_DRIVER_VERSION_GYRO 0U
-
 #define int16_val(v, idx) ((int16_t)(((uint16_t)v[2*idx] << 8) | v[2*idx+1]))
 #define uint16_val(v, idx)(((uint16_t)v[2*idx] << 8) | v[2*idx+1])
 
@@ -382,8 +379,8 @@ void AP_InertialSensor_MPU6000::start()
     _dev->get_semaphore()->give();
 
     // grab the used instances
-    _gyro_instance = _imu.register_gyro(1000, _dev->get_bus_id_devtype(MPU6000_DRIVER_VERSION_GYRO));
-    _accel_instance = _imu.register_accel(1000, _dev->get_bus_id_devtype(MPU6000_DRIVER_VERSION_ACCEL));
+    _gyro_instance = _imu.register_gyro(1000, _dev->get_bus_id_devtype(DEVTYPE_GYR_MPU6000));
+    _accel_instance = _imu.register_accel(1000, _dev->get_bus_id_devtype(DEVTYPE_ACC_MPU6000));
 
     // setup sensor rotations from probe()
     set_gyro_orientation(_gyro_instance, _rotation);
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp
index f459b041ba..e08c7ffe7e 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp
@@ -320,8 +320,8 @@ void AP_InertialSensor_MPU9250::start()
     _dev->get_semaphore()->give();
 
     // grab the used instances
-    _gyro_instance = _imu.register_gyro(DEFAULT_SAMPLE_RATE, _dev->get_bus_id());
-    _accel_instance = _imu.register_accel(DEFAULT_SAMPLE_RATE, _dev->get_bus_id());
+    _gyro_instance = _imu.register_gyro(DEFAULT_SAMPLE_RATE, _dev->get_bus_id_devtype(DEVTYPE_GYR_MPU9250));
+    _accel_instance = _imu.register_accel(DEFAULT_SAMPLE_RATE, _dev->get_bus_id_devtype(DEVTYPE_ACC_MPU9250));
 
     // start the timer process to read samples
     _dev->register_periodic_callback(1000, FUNCTOR_BIND_MEMBER(&AP_InertialSensor_MPU9250::_read_sample, bool));