diff --git a/src/main/blackbox/blackbox.c b/src/main/blackbox/blackbox.c
index 406ce05d3..d2fcb40a5 100644
--- a/src/main/blackbox/blackbox.c
+++ b/src/main/blackbox/blackbox.c
@@ -72,6 +72,7 @@
 #include "flight/altitudehold.h"
 #include "flight/failsafe.h"
 #include "flight/imu.h"
+#include "flight/pid.h"
 #include "flight/navigation.h"
 
 #include "config/runtime_config.h"
diff --git a/src/main/blackbox/blackbox_io.c b/src/main/blackbox/blackbox_io.c
index cd4f05d98..88306767c 100644
--- a/src/main/blackbox/blackbox_io.c
+++ b/src/main/blackbox/blackbox_io.c
@@ -53,6 +53,7 @@
 #include "flight/altitudehold.h"
 #include "flight/failsafe.h"
 #include "flight/imu.h"
+#include "flight/pid.h"
 #include "flight/navigation.h"
 
 #include "config/runtime_config.h"
diff --git a/src/main/common/printf.h b/src/main/common/printf.h
index ac5493590..467b054d5 100644
--- a/src/main/common/printf.h
+++ b/src/main/common/printf.h
@@ -102,13 +102,10 @@ For further details see source code.
 regs Kusti, 23.10.2004
 */
 
-#ifndef __TFP_PRINTF__
-#define __TFP_PRINTF__
+#pragma once
 
 #include <stdarg.h>
 
-#include "drivers/serial.h"
-
 void init_printf(void *putp, void (*putf) (void *, char));
 
 int tfp_printf(const char *fmt, ...);
@@ -119,8 +116,6 @@ int tfp_format(void *putp, void (*putf) (void *, char), const char *fmt, va_list
 #define printf tfp_printf
 #define sprintf tfp_sprintf
 
-void setPrintfSerialPort(serialPort_t *serialPort);
+struct serialPort_s;
+void setPrintfSerialPort(struct serialPort_s *serialPort);
 void printfSupportInit(void);
-
-
-#endif
diff --git a/src/main/flight/altitudehold.h b/src/main/flight/altitudehold.h
index 3677fbb28..da1697881 100644
--- a/src/main/flight/altitudehold.h
+++ b/src/main/flight/altitudehold.h
@@ -15,19 +15,21 @@
  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "io/escservo.h"
-#include "io/rc_controls.h"
-#include "flight/pid.h"
-
-#include "sensors/barometer.h"
+#pragma once
 
 extern int32_t AltHold;
 extern int32_t vario;
 
 void calculateEstimatedAltitude(uint32_t currentTime);
 
-void configureAltitudeHold(pidProfile_t *initialPidProfile, barometerConfig_t *intialBarometerConfig, rcControlsConfig_t *initialRcControlsConfig, escAndServoConfig_t *initialEscAndServoConfig);
-void applyAltHold(airplaneConfig_t *airplaneConfig);
+struct pidProfile_s;
+struct barometerConfig_s;
+struct rcControlsConfig_s;
+struct escAndServoConfig_s;
+void configureAltitudeHold(struct pidProfile_s *initialPidProfile, struct barometerConfig_s *intialBarometerConfig, struct rcControlsConfig_s *initialRcControlsConfig, struct escAndServoConfig_s *initialEscAndServoConfig);
+
+struct airplaneConfig_t;
+void applyAltHold(struct airplaneConfig_s *airplaneConfig);
 void updateAltHoldState(void);
 void updateSonarAltHoldState(void);
 
diff --git a/src/main/flight/imu.h b/src/main/flight/imu.h
index 94b361fcf..e5229a2ea 100644
--- a/src/main/flight/imu.h
+++ b/src/main/flight/imu.h
@@ -69,9 +69,10 @@ typedef struct accProcessor_s {
     accProcessorState_e state;
 } accProcessor_t;
 
+struct pidProfile_s;
 void imuConfigure(
     imuRuntimeConfig_t *initialImuRuntimeConfig,
-    pidProfile_t *initialPidProfile,
+    struct pidProfile_s *initialPidProfile,
     accDeadband_t *initialAccDeadband,
     uint16_t throttle_correction_angle
 );
diff --git a/src/main/flight/pid.c b/src/main/flight/pid.c
index 068012ad5..be1bcf203 100644
--- a/src/main/flight/pid.c
+++ b/src/main/flight/pid.c
@@ -51,6 +51,8 @@ uint32_t targetPidLooptime;
 
 bool pidStabilisationEnabled;
 
+uint8_t PIDweight[3];
+
 int16_t axisPID[3];
 
 // PIDweight is a scale factor for PIDs which is derived from the throttle and TPA setting, and 100 = 100% scale means no PID reduction
diff --git a/src/main/flight/pid.h b/src/main/flight/pid.h
index 60efb88a5..c4509887d 100644
--- a/src/main/flight/pid.h
+++ b/src/main/flight/pid.h
@@ -14,7 +14,6 @@
  * You should have received a copy of the GNU General Public License
  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include "rx/rx.h"
 
 #pragma once
 
diff --git a/src/main/io/display.c b/src/main/io/display.c
index 1e5eee974..a22ca8802 100644
--- a/src/main/io/display.c
+++ b/src/main/io/display.c
@@ -63,6 +63,8 @@
 
 #include "io/display.h"
 
+#include "rx/rx.h"
+
 #include "scheduler/scheduler.h"
 
 extern profile_t *currentProfile;
diff --git a/src/main/io/rc_controls.h b/src/main/io/rc_controls.h
index aace839d9..a3622aaca 100644
--- a/src/main/io/rc_controls.h
+++ b/src/main/io/rc_controls.h
@@ -17,8 +17,6 @@
 
 #pragma once
 
-#include "rx/rx.h"
-
 typedef enum {
     BOXARM = 0,
     BOXANGLE,
@@ -167,8 +165,9 @@ typedef struct rcControlsConfig_s {
 bool areUsingSticksToArm(void);
 
 bool areSticksInApModePosition(uint16_t ap_mode);
-throttleStatus_e calculateThrottleStatus(rxConfig_t *rxConfig, uint16_t deadband3d_throttle);
-void processRcStickPositions(rxConfig_t *rxConfig, throttleStatus_e throttleStatus, bool disarm_kill_switch);
+struct rxConfig_s;
+throttleStatus_e calculateThrottleStatus(struct rxConfig_s *rxConfig, uint16_t deadband3d_throttle);
+void processRcStickPositions(struct rxConfig_s *rxConfig, throttleStatus_e throttleStatus, bool disarm_kill_switch);
 
 bool isRangeActive(uint8_t auxChannelIndex, channelRange_t *range);
 void updateActivatedModes(modeActivationCondition_t *modeActivationConditions);
@@ -257,7 +256,7 @@ bool isAirmodeActive(void);
 bool isSuperExpoActive(void);
 void resetAdjustmentStates(void);
 void updateAdjustmentStates(adjustmentRange_t *adjustmentRanges);
-void processRcAdjustments(controlRateConfig_t *controlRateConfig, rxConfig_t *rxConfig);
+void processRcAdjustments(controlRateConfig_t *controlRateConfig, struct rxConfig_s *rxConfig);
 
 bool isUsingSticksForArming(void);
 
diff --git a/src/main/io/rc_curves.c b/src/main/io/rc_curves.c
index 89b46522f..f96426bfd 100644
--- a/src/main/io/rc_curves.c
+++ b/src/main/io/rc_curves.c
@@ -18,13 +18,15 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-#include "io/rc_controls.h"
-#include "io/escservo.h"
-
-#include "io/rc_curves.h"
-
 #include "config/config.h"
 
+#include "io/escservo.h"
+#include "io/rc_curves.h"
+#include "io/rc_controls.h"
+
+#include "rx/rx.h"
+
+
 #define THROTTLE_LOOKUP_LENGTH 12
 static int16_t lookupThrottleRC[THROTTLE_LOOKUP_LENGTH];    // lookup table for expo & mid THROTTLE
 
diff --git a/src/main/io/rc_curves.h b/src/main/io/rc_curves.h
index 747a934df..406218d03 100644
--- a/src/main/io/rc_curves.h
+++ b/src/main/io/rc_curves.h
@@ -17,7 +17,9 @@
 
 #pragma once
 
-void generateThrottleCurve(controlRateConfig_t *controlRateConfig, escAndServoConfig_t *escAndServoConfig);
+struct controlRateConfig_s;
+struct escAndServoConfig_s;
+void generateThrottleCurve(struct controlRateConfig_s *controlRateConfig, struct escAndServoConfig_s *escAndServoConfig);
 
 int16_t rcLookup(int32_t tmp, uint8_t expo, uint8_t rate);
 int16_t rcLookupThrottle(int32_t tmp);
diff --git a/src/main/io/serial_4way.c b/src/main/io/serial_4way.c
index 9bd2ba69e..0065cff89 100644
--- a/src/main/io/serial_4way.c
+++ b/src/main/io/serial_4way.c
@@ -23,21 +23,23 @@
 #include <stdarg.h>
 
 #include "platform.h"
+
 #ifdef  USE_SERIAL_4WAY_BLHELI_INTERFACE
-#include "drivers/serial.h"
+
 #include "drivers/buf_writer.h"
-#include "drivers/gpio.h"
+#include "drivers/io.h"
+#include "drivers/serial.h"
 #include "drivers/timer.h"
 #include "drivers/pwm_mapping.h"
 #include "drivers/pwm_output.h"
 #include "drivers/light_led.h"
 #include "drivers/system.h"
+
 #include "flight/mixer.h"
+
 #include "io/beeper.h"
 #include "io/serial_msp.h"
-#include "io/serial_msp.h"
 #include "io/serial_4way.h"
-#include "io/serial_4way_impl.h"
 
 #ifdef USE_SERIAL_4WAY_BLHELI_BOOTLOADER
 #include "io/serial_4way_avrootloader.h"
diff --git a/src/main/io/serial_4way.h b/src/main/io/serial_4way.h
index b1bba5ff6..8e0c934a9 100644
--- a/src/main/io/serial_4way.h
+++ b/src/main/io/serial_4way.h
@@ -17,7 +17,8 @@
 */
 #pragma once
 
-#include "serial_4way_impl.h"
+#include "drivers/io_types.h"
+#include "io/serial_4way_impl.h"
 
 #define USE_SERIAL_4WAY_BLHELI_BOOTLOADER
 #define USE_SERIAL_4WAY_SK_BOOTLOADER
@@ -46,5 +47,6 @@ typedef union __attribute__ ((packed)) {
 
 bool isMcuConnected(void);
 uint8_t esc4wayInit(void);
-void esc4wayProcess(serialPort_t *mspPort);
+struct serialPort_s;
+void esc4wayProcess(struct serialPort_s *mspPort);
 void esc4wayRelease(void);
diff --git a/src/main/io/serial_4way_avrootloader.c b/src/main/io/serial_4way_avrootloader.c
index 223d3e10c..f3eeba532 100644
--- a/src/main/io/serial_4way_avrootloader.c
+++ b/src/main/io/serial_4way_avrootloader.c
@@ -25,7 +25,8 @@
 #include "platform.h"
 
 #ifdef  USE_SERIAL_4WAY_BLHELI_INTERFACE
-#include "drivers/io_types.h"
+
+#include "drivers/io.h"
 #include "drivers/system.h"
 #include "drivers/serial.h"
 #include "drivers/timer.h"
diff --git a/src/main/io/serial_4way_impl.h b/src/main/io/serial_4way_impl.h
index a8f83bfae..351aba0b6 100644
--- a/src/main/io/serial_4way_impl.h
+++ b/src/main/io/serial_4way_impl.h
@@ -17,7 +17,7 @@
 */
 #pragma once
 
-#include "drivers/io.h"
+#include "drivers/io_types.h"
 
 typedef struct {
     IO_t io;
diff --git a/src/main/io/serial_4way_stk500v2.c b/src/main/io/serial_4way_stk500v2.c
index 342a0c8b0..0b406531f 100644
--- a/src/main/io/serial_4way_stk500v2.c
+++ b/src/main/io/serial_4way_stk500v2.c
@@ -23,7 +23,10 @@
 #include <stdlib.h>
 
 #include "platform.h"
+
 #ifdef  USE_SERIAL_4WAY_BLHELI_INTERFACE
+
+#include "drivers/io.h"
 #include "drivers/serial.h"
 #include "config/config.h"
 #include "io/serial.h"
diff --git a/src/main/io/serial_msp.c b/src/main/io/serial_msp.c
index a2f472f45..031d0ddf6 100644
--- a/src/main/io/serial_msp.c
+++ b/src/main/io/serial_msp.c
@@ -37,6 +37,7 @@
 
 #include "drivers/serial.h"
 #include "drivers/bus_i2c.h"
+#include "drivers/io.h"
 #include "drivers/gpio.h"
 #include "drivers/timer.h"
 #include "drivers/pwm_rx.h"
diff --git a/src/main/io/serial_msp.h b/src/main/io/serial_msp.h
index 2778da7e2..114e94ab8 100644
--- a/src/main/io/serial_msp.h
+++ b/src/main/io/serial_msp.h
@@ -17,9 +17,6 @@
 
 #pragma once
 
-#include "io/serial.h"
-#include "drivers/serial.h"
-
 // Each MSP port requires state and a receive buffer, revisit this default if someone needs more than 2 MSP ports.
 #define MAX_MSP_PORT_COUNT 2
 
@@ -46,7 +43,9 @@ typedef struct mspPort_s {
     uint8_t cmdMSP;
 } mspPort_t;
 
-void mspInit(serialConfig_t *serialConfig);
+struct serialConfig_s;
+void mspInit(struct serialConfig_s *serialConfig);
 void mspProcess(void);
-void mspAllocateSerialPorts(serialConfig_t *serialConfig);
-void mspReleasePortIfAllocated(serialPort_t *serialPort);
+void mspAllocateSerialPorts(struct serialConfig_s *serialConfig);
+struct serialPort_s;
+void mspReleasePortIfAllocated(struct serialPort_s *serialPort);
diff --git a/src/main/rx/rx.c b/src/main/rx/rx.c
index a7a09a44b..bcba5bb86 100644
--- a/src/main/rx/rx.c
+++ b/src/main/rx/rx.c
@@ -32,15 +32,16 @@
 
 #include "drivers/serial.h"
 #include "drivers/adc.h"
-#include "io/serial.h"
-#include "io/rc_controls.h"
-
-#include "flight/failsafe.h"
-
-#include "drivers/gpio.h"
 #include "drivers/timer.h"
 #include "drivers/pwm_rx.h"
 #include "drivers/system.h"
+
+#include "flight/failsafe.h"
+
+#include "io/serial.h"
+#include "io/rc_controls.h"
+
+#include "rx/rx.h"
 #include "rx/pwm.h"
 #include "rx/sbus.h"
 #include "rx/spektrum.h"
@@ -51,8 +52,6 @@
 #include "rx/ibus.h"
 #include "rx/jetiexbus.h"
 
-#include "rx/rx.h"
-
 
 //#define DEBUG_RX_SIGNAL_LOSS
 
diff --git a/src/main/rx/xbus.h b/src/main/rx/xbus.h
index bc76f5678..cfaa920ff 100644
--- a/src/main/rx/xbus.h
+++ b/src/main/rx/xbus.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "rx/rx.h"
-
-bool xBusInit(rxConfig_t *rxConfig, rxRuntimeConfig_t *rxRuntimeConfig, rcReadRawDataPtr *callback);
+struct rxConfig_s;
+struct rxRuntimeConfig_s;
+bool xBusInit(struct rxConfig_s *rxConfig, struct rxRuntimeConfig_s *rxRuntimeConfig, rcReadRawDataPtr *callback);
 uint8_t xBusFrameStatus(void);
diff --git a/src/main/sensors/battery.c b/src/main/sensors/battery.c
index 75aac6cf0..6d165cbc5 100644
--- a/src/main/sensors/battery.c
+++ b/src/main/sensors/battery.c
@@ -35,6 +35,8 @@
 #include "io/rc_controls.h"
 #include "io/beeper.h"
 
+#include "rx/rx.h"
+
 #define VBATT_PRESENT_THRESHOLD_MV    10
 #define VBATT_LPF_FREQ  0.4f
 
diff --git a/src/main/telemetry/frsky.h b/src/main/telemetry/frsky.h
index 555eb43e8..89ba617c8 100644
--- a/src/main/telemetry/frsky.h
+++ b/src/main/telemetry/frsky.h
@@ -17,17 +17,17 @@
 
 #pragma once
 
-#include "rx/rx.h"
-
 typedef enum {
     FRSKY_VFAS_PRECISION_LOW = 0,
     FRSKY_VFAS_PRECISION_HIGH
 } frskyVFasPrecision_e;
 
-void handleFrSkyTelemetry(rxConfig_t *rxConfig, uint16_t deadband3d_throttle);
+struct rxConfig_s;
+void handleFrSkyTelemetry(struct rxConfig_s *rxConfig, uint16_t deadband3d_throttle);
 void checkFrSkyTelemetryState(void);
 
-void initFrSkyTelemetry(telemetryConfig_t *telemetryConfig);
+struct telemetryConfig_s;
+void initFrSkyTelemetry(struct telemetryConfig_s *telemetryConfig);
 void configureFrSkyTelemetryPort(void);
 void freeFrSkyTelemetryPort(void);