diff --git a/libraries/AP_Compass/AP_Compass.cpp b/libraries/AP_Compass/AP_Compass.cpp
index 03d921dc12..0a2dc539ed 100644
--- a/libraries/AP_Compass/AP_Compass.cpp
+++ b/libraries/AP_Compass/AP_Compass.cpp
@@ -925,12 +925,19 @@ void Compass::_detect_backends(void)
                                                            true, HAL_COMPASS_QMC5883L_ORIENTATION_EXTERNAL));
     ADD_BACKEND(DRIVER_QMC5883, AP_Compass_QMC5883L::probe(GET_I2C_DEVICE(0, HAL_COMPASS_QMC5883L_I2C_ADDR),
                                                            false, HAL_COMPASS_QMC5883L_ORIENTATION_INTERNAL));
+#elif HAL_COMPASS_DEFAULT == HAL_COMPASS_LIS3MDL_I2C
+    FOREACH_I2C(i) {
+        ADD_BACKEND(DRIVER_LIS3MDL, AP_Compass_LIS3MDL::probe(GET_I2C_DEVICE(i, HAL_COMPASS_LIS3MDL_I2C_ADDR), true, ROTATION_NONE));
+        ADD_BACKEND(DRIVER_LIS3MDL, AP_Compass_LIS3MDL::probe(GET_I2C_DEVICE(i, HAL_COMPASS_LIS3MDL_I2C_ADDR2), true, ROTATION_NONE));
+    }
 #elif CONFIG_HAL_BOARD == HAL_BOARD_LINUX && CONFIG_HAL_BOARD_SUBTYPE != HAL_BOARD_SUBTYPE_LINUX_NONE
     ADD_BACKEND(DRIVER_HMC5843, AP_Compass_HMC5843::probe(GET_I2C_DEVICE(HAL_COMPASS_HMC5843_I2C_BUS, HAL_COMPASS_HMC5843_I2C_ADDR)));
     ADD_BACKEND(DRIVER_AK8963, AP_Compass_AK8963::probe_mpu9250(0));
     ADD_BACKEND(DRIVER_LSM9DS1, AP_Compass_LSM9DS1::probe(hal.spi->get_device("lsm9ds1_m")));
 #elif HAL_COMPASS_DEFAULT == HAL_COMPASS_BMM150_I2C
     ADD_BACKEND(DRIVER_BMM150, AP_Compass_BMM150::probe(GET_I2C_DEVICE(HAL_COMPASS_BMM150_I2C_BUS, HAL_COMPASS_BMM150_I2C_ADDR)));
+#elif HAL_COMPASS_DEFAULT == HAL_COMPASS_RM3100_SPI
+    ADD_BACKEND(DRIVER_RM3100, AP_Compass_RM3100::probe(hal.spi->get_device("rm3100"), ROTATION_NONE));
 #elif HAL_COMPASS_DEFAULT == HAL_COMPASS_NONE
     // no compass
 #else
diff --git a/libraries/AP_Compass/AP_Compass_RM3100.cpp b/libraries/AP_Compass/AP_Compass_RM3100.cpp
index 20cc649b86..89521588c1 100644
--- a/libraries/AP_Compass/AP_Compass_RM3100.cpp
+++ b/libraries/AP_Compass/AP_Compass_RM3100.cpp
@@ -97,6 +97,11 @@ bool AP_Compass_RM3100::init()
         return false;
     }
 
+    if (dev->bus_type() == AP_HAL::Device::BUS_TYPE_SPI) {
+        // read has high bit set for SPI
+        dev->set_read_flag(0x80);
+    }
+
     // high retries for init
     dev->set_retries(10);