diff --git a/libraries/AP_AccelCal/AP_AccelCal.cpp b/libraries/AP_AccelCal/AP_AccelCal.cpp
index d4fa4cba030b4b..5c2fc07e00fa17 100644
--- a/libraries/AP_AccelCal/AP_AccelCal.cpp
+++ b/libraries/AP_AccelCal/AP_AccelCal.cpp
@@ -362,7 +362,7 @@ bool AP_AccelCal::client_active(uint8_t client_num)
     return (bool)_clients[client_num]->_acal_get_calibrator(0);
 }
 
-#if HAL_GCS_ENABLED
+#if HAL_GCS_ENABLED || defined(GCS_MAVLINK)
 void AP_AccelCal::handle_command_ack(const mavlink_command_ack_t &packet)
 {
     if (!_waiting_for_mavlink_ack) {
diff --git a/libraries/AP_AccelCal/AP_AccelCal.h b/libraries/AP_AccelCal/AP_AccelCal.h
index de6168ce62e042..cecac1029bd8a2 100644
--- a/libraries/AP_AccelCal/AP_AccelCal.h
+++ b/libraries/AP_AccelCal/AP_AccelCal.h
@@ -12,7 +12,9 @@
 #endif
 #endif
 
+#include <GCS_MAVLink/GCS.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
+
 #include "AccelCalibrator.h"
 
 #define AP_ACCELCAL_MAX_NUM_CLIENTS 4
@@ -45,7 +47,7 @@ class AP_AccelCal {
     // interface to the clients for registration
     static void register_client(AP_AccelCal_Client* client);
 
-#if HAL_GCS_ENABLED
+#if HAL_GCS_ENABLED || defined(GCS_MAVLINK)
     void handle_command_ack(const mavlink_command_ack_t &packet);
 #endif
 
diff --git a/libraries/AP_Compass/AP_Compass.cpp b/libraries/AP_Compass/AP_Compass.cpp
index 039ade2d5a70e2..a47b65ef0f164b 100644
--- a/libraries/AP_Compass/AP_Compass.cpp
+++ b/libraries/AP_Compass/AP_Compass.cpp
@@ -71,7 +71,7 @@ extern const AP_HAL::HAL& hal;
 const AP_Param::GroupInfo Compass::var_info[] = {
     // index 0 was used for the old orientation matrix
 
-#ifndef HAL_BUILD_AP_PERIPH
+#if !defined(HAL_BUILD_AP_PERIPH) && !COMPASS_CAL_ENABLED
     // @Param: OFS_X
     // @DisplayName: Compass offsets in milligauss on the X axis
     // @Description: Offset to be added to the compass x-axis values to compensate for metal in the frame
diff --git a/libraries/AP_Compass/AP_Compass.h b/libraries/AP_Compass/AP_Compass.h
index f08a63e81c96b6..21f26bc40fe94f 100644
--- a/libraries/AP_Compass/AP_Compass.h
+++ b/libraries/AP_Compass/AP_Compass.h
@@ -10,6 +10,7 @@
 #include <AP_Math/AP_Math.h>
 #include <AP_Param/AP_Param.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
+#include <GCS_MAVLink/GCS.h>
 #include <AP_MSP/msp.h>
 #include <AP_ExternalAHRS/AP_ExternalAHRS.h>
 
diff --git a/libraries/AP_Compass/AP_Compass_Calibration.cpp b/libraries/AP_Compass/AP_Compass_Calibration.cpp
index 809ca03c0e931d..500dc1e6213017 100644
--- a/libraries/AP_Compass/AP_Compass_Calibration.cpp
+++ b/libraries/AP_Compass/AP_Compass_Calibration.cpp
@@ -240,7 +240,7 @@ bool Compass::_accept_calibration_mask(uint8_t mask)
     return success;
 }
 
-#if HAL_GCS_ENABLED
+#if HAL_GCS_ENABLED || defined(GCS_MAVLINK)
 bool Compass::send_mag_cal_progress(const GCS_MAVLINK& link)
 {
     const mavlink_channel_t chan = link.get_chan();
diff --git a/libraries/AP_DAL/AP_DAL.cpp b/libraries/AP_DAL/AP_DAL.cpp
index 986fe66bcf0251..abe872a63a4cd5 100644
--- a/libraries/AP_DAL/AP_DAL.cpp
+++ b/libraries/AP_DAL/AP_DAL.cpp
@@ -76,7 +76,9 @@ void AP_DAL::start_frame(AP_DAL::FrameType frametype)
 #if AP_OPTICALFLOW_ENABLED
     _RFRN.opticalflow_enabled = AP::opticalflow() && AP::opticalflow()->enabled();
 #endif
+#if AP_WHEELENCODER_ENABLED
     _RFRN.wheelencoder_enabled = AP::wheelencoder() && (AP::wheelencoder()->num_sensors() > 0);
+#endif
     _RFRN.ekf_type = ahrs.get_ekf_type();
     WRITE_REPLAY_BLOCK_IFCHANGED(RFRN, _RFRN, old);
 
diff --git a/libraries/AP_HAL/AP_HAL_Boards.h b/libraries/AP_HAL/AP_HAL_Boards.h
index 5ba862d7ef177f..cef4e94d5440be 100644
--- a/libraries/AP_HAL/AP_HAL_Boards.h
+++ b/libraries/AP_HAL/AP_HAL_Boards.h
@@ -373,3 +373,7 @@
 #endif
 
 #define HAL_GPIO_LED_OFF (!HAL_GPIO_LED_ON)
+
+#ifndef HAL_MAVLINK_ENABLED
+#define HAL_MAVLINK_ENABLED 0
+#endif
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor.cpp b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
index b2a76a1f266b28..b5f63843233ec0 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
@@ -2482,7 +2482,7 @@ bool AP_InertialSensor::get_primary_accel_cal_sample_avg(uint8_t sample_num, Vec
     return true;
 }
 
-#if HAL_GCS_ENABLED
+#if HAL_GCS_ENABLED || defined(GCS_MAVLINK)
 bool AP_InertialSensor::calibrate_gyros()
 {
     init_gyro();
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor.h b/libraries/AP_InertialSensor/AP_InertialSensor.h
index 9bce50d4ac57dc..e1ec785e4423b3 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor.h
+++ b/libraries/AP_InertialSensor/AP_InertialSensor.h
@@ -289,7 +289,7 @@ class AP_InertialSensor : AP_AccelCal_Client
     void acal_update();
 #endif
 
-#if HAL_GCS_ENABLED
+#if HAL_GCS_ENABLED || defined(GCS_MAVLINK)
     bool calibrate_gyros();
 
     MAV_RESULT calibrate_trim();
diff --git a/libraries/AP_WheelEncoder/AP_WheelEncoder.cpp b/libraries/AP_WheelEncoder/AP_WheelEncoder.cpp
index 610a7cd8e2bd7e..167e70d5bce661 100644
--- a/libraries/AP_WheelEncoder/AP_WheelEncoder.cpp
+++ b/libraries/AP_WheelEncoder/AP_WheelEncoder.cpp
@@ -14,6 +14,7 @@
  */
 
 #include "AP_WheelEncoder.h"
+#if AP_WHEELENCODER_ENABLED
 #include "WheelEncoder_Quadrature.h"
 #include "WheelEncoder_SITL_Quadrature.h"
 #include <AP_Logger/AP_Logger.h>
@@ -363,3 +364,4 @@ AP_WheelEncoder *wheelencoder()
 }
 
 }
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/AP_WheelEncoder.h b/libraries/AP_WheelEncoder/AP_WheelEncoder.h
index 4c92c911479d75..fc0b21874e4cb5 100644
--- a/libraries/AP_WheelEncoder/AP_WheelEncoder.h
+++ b/libraries/AP_WheelEncoder/AP_WheelEncoder.h
@@ -14,6 +14,9 @@
  */
 #pragma once
 
+#include "AP_WheelEncoder_config.h"
+
+#if AP_WHEELENCODER_ENABLED
 #include <AP_Common/AP_Common.h>
 #include <AP_Param/AP_Param.h>
 #include <AP_Math/AP_Math.h>
@@ -133,3 +136,4 @@ class AP_WheelEncoder
 namespace AP {
     AP_WheelEncoder *wheelencoder();
 }
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/AP_WheelRateControl.cpp b/libraries/AP_WheelEncoder/AP_WheelRateControl.cpp
index 97c9a1e19c5e16..ee9f626a565209 100644
--- a/libraries/AP_WheelEncoder/AP_WheelRateControl.cpp
+++ b/libraries/AP_WheelEncoder/AP_WheelRateControl.cpp
@@ -1,4 +1,5 @@
 #include <AP_WheelEncoder/AP_WheelRateControl.h>
+#if AP_WHEELENCODER_ENABLED
 
 extern const AP_HAL::HAL& hal;
 
@@ -281,3 +282,5 @@ void AP_WheelRateControl::set_notch_sample_rate(float sample_rate)
     _rate_pid1.set_notch_sample_rate(sample_rate);
 #endif
 }
+
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/AP_WheelRateControl.h b/libraries/AP_WheelEncoder/AP_WheelRateControl.h
index f62d981bfb6863..a099fb1a83cda9 100644
--- a/libraries/AP_WheelEncoder/AP_WheelRateControl.h
+++ b/libraries/AP_WheelEncoder/AP_WheelRateControl.h
@@ -15,6 +15,10 @@
 
 #pragma once
 
+#include "AP_WheelEncoder_config.h"
+
+#if AP_WHEELENCODER_ENABLED
+
 #include <AP_Common/AP_Common.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_Param/AP_Param.h>
@@ -74,3 +78,4 @@ class AP_WheelRateControl {
     const AP_WheelEncoder&  _wheel_encoder;     // pointer to accompanying wheel encoder
     uint32_t                _last_update_ms;    // system time of last call to get_rate_controlled_throttle
 };
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Backend.cpp b/libraries/AP_WheelEncoder/WheelEncoder_Backend.cpp
index 4742dcfa1f2199..4906426c9b3204 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Backend.cpp
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Backend.cpp
@@ -13,8 +13,10 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <AP_Common/AP_Common.h>
 #include "AP_WheelEncoder.h"
+
+#if AP_WHEELENCODER_ENABLED
+#include <AP_Common/AP_Common.h>
 #include "WheelEncoder_Backend.h"
 
 // base class constructor.
@@ -56,3 +58,4 @@ void AP_WheelEncoder_Backend::copy_state_to_frontend(int32_t distance_count, uin
     _state.error_count = error_count;
     _state.last_reading_ms = last_reading_ms;
 }
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Backend.h b/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
index 382c911ff76f94..757c2e4a3cfc54 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
@@ -14,9 +14,11 @@
  */
 #pragma once
 
-#include <AP_Common/AP_Common.h>
 #include "AP_WheelEncoder.h"
 
+#if AP_WHEELENCODER_ENABLED
+#include <AP_Common/AP_Common.h>
+
 class AP_WheelEncoder_Backend
 {
 public:
@@ -42,3 +44,4 @@ class AP_WheelEncoder_Backend
     AP_WheelEncoder &_frontend;
     AP_WheelEncoder::WheelEncoder_State &_state;
 };
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
index cb82bef21bca85..a078c59d1941d9 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
@@ -13,10 +13,10 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <AP_HAL/AP_HAL.h>
-
 #include "WheelEncoder_Quadrature.h"
 
+#if AP_WHEELENCODER_ENABLED
+#include <AP_HAL/AP_HAL.h>
 #include <GCS_MAVLink/GCS.h>
 
 extern const AP_HAL::HAL& hal;
@@ -140,3 +140,4 @@ void AP_WheelEncoder_Quadrature::irq_handler(uint8_t pin,
     // record update time
     irq_state.last_reading_ms = timestamp * 1e-3f;
 }
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.h b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.h
index 9693ba9a124f6c..c2725b8905b937 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.h
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.h
@@ -15,6 +15,8 @@
 #pragma once
 
 #include "AP_WheelEncoder.h"
+
+#if AP_WHEELENCODER_ENABLED
 #include "WheelEncoder_Backend.h"
 #include <Filter/Filter.h>
 #include <AP_Math/AP_Math.h>
@@ -57,3 +59,4 @@ class AP_WheelEncoder_Quadrature : public AP_WheelEncoder_Backend
     uint8_t last_pin_a_value;
     uint8_t last_pin_b_value;
 };
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.cpp b/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.cpp
index 9fc073d545d0d5..dafc2ca491d549 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.cpp
+++ b/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.cpp
@@ -18,6 +18,7 @@
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
 
 #include "WheelEncoder_SITL_Quadrature.h"
+#if AP_WHEELENCODER_ENABLED
 #include <GCS_MAVLink/GCS.h>
 
 extern const AP_HAL::HAL& hal;
@@ -86,4 +87,5 @@ void AP_WheelEncoder_SITL_Quadrature::update(void)
     copy_state_to_frontend(_distance_count, _total_count, 0, time_now);
 }
 
-#endif
+#endif // CONFIG_HAL_BOARD == HAL_BOARD_SITL
+#endif // AP_WHEELENCODER_ENABLED
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.h b/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.h
index 006d9700ca1cae..4a55fb8c238256 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.h
+++ b/libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.h
@@ -14,9 +14,9 @@
  */
 #pragma once
 
-#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+#include "WheelEncoder_Quadrature.h"
+#if CONFIG_HAL_BOARD == HAL_BOARD_SITL && AP_WHEELENCODER_ENABLED
 
-#include "WheelEncoder_Backend.h"
 #include <AP_Math/AP_Math.h>
 #include <SITL/SITL.h>
 
@@ -34,4 +34,4 @@ class AP_WheelEncoder_SITL_Quadrature : public AP_WheelEncoder_Backend
     uint32_t _total_count; // total number of encoder ticks
 };
 
-#endif // CONFIG_HAL_BOARD
\ No newline at end of file
+#endif // CONFIG_HAL_BOARD == HAL_BOARD_SITL && AP_WHEELENCODER_ENABLED
\ No newline at end of file
diff --git a/libraries/GCS_MAVLink/GCS.h b/libraries/GCS_MAVLink/GCS.h
index bd26264667b566..c9248f53743ba6 100644
--- a/libraries/GCS_MAVLink/GCS.h
+++ b/libraries/GCS_MAVLink/GCS.h
@@ -1372,6 +1372,10 @@ extern "C" {
 #define GCS_SEND_MESSAGE(msg)
 #define AP_HAVE_GCS_SEND_TEXT 1
 
+#include "../../../AP_Periph/MAVLink.h"
+#define GCS_MAVLINK MAVLink_Periph
+#define HAVE_PAYLOAD_SPACE(_chan, id) true
+
 /*
   we need a severity enum for the can_printf_severity function with no GCS present
  */