diff --git a/src/main/common/printf.h b/src/main/common/printf.h
index dff4efdd2d..27615cf56d 100644
--- a/src/main/common/printf.h
+++ b/src/main/common/printf.h
@@ -119,6 +119,7 @@ int tfp_format(void *putp, void (*putf) (void *, char), const char *fmt, va_list
 #define printf tfp_printf
 #define sprintf tfp_sprintf
 
+void printfSupportInit(void);
 void setPrintfSerialPort(serialPort_t *serialPort);
 
 #endif
diff --git a/src/main/drivers/accgyro_mma845x.c b/src/main/drivers/accgyro_mma845x.c
index 202b90e804..69a82a0adb 100644
--- a/src/main/drivers/accgyro_mma845x.c
+++ b/src/main/drivers/accgyro_mma845x.c
@@ -21,7 +21,7 @@
 #include "platform.h"
 
 #include "system.h"
-#include "gpio.h"
+#include "io.h"
 #include "bus_i2c.h"
 
 #include "sensor.h"
diff --git a/src/main/drivers/accgyro_mpu.c b/src/main/drivers/accgyro_mpu.c
index 1c705ef137..4284697217 100644
--- a/src/main/drivers/accgyro_mpu.c
+++ b/src/main/drivers/accgyro_mpu.c
@@ -29,7 +29,7 @@
 #include "nvic.h"
 
 #include "system.h"
-#include "gpio.h"
+#include "io.h"
 #include "exti.h"
 #include "bus_i2c.h"
 
diff --git a/src/main/drivers/accgyro_mpu.h b/src/main/drivers/accgyro_mpu.h
index 132c9e13a0..0b70ebb14a 100644
--- a/src/main/drivers/accgyro_mpu.h
+++ b/src/main/drivers/accgyro_mpu.h
@@ -17,6 +17,7 @@
 
 #pragma once
 
+#include "io_types.h"
 #include "exti.h"
 
 // MPU6050
diff --git a/src/main/drivers/adc.c b/src/main/drivers/adc.c
index a65abf9128..6bba109396 100644
--- a/src/main/drivers/adc.c
+++ b/src/main/drivers/adc.c
@@ -27,6 +27,8 @@
 #include "adc.h"
 #include "adc_impl.h"
 
+#include "common/utils.h"
+
 //#define DEBUG_ADC_CHANNELS
 
 #ifdef USE_ADC
diff --git a/src/main/drivers/adc.h b/src/main/drivers/adc.h
index 55914a3365..47a4b52a0e 100644
--- a/src/main/drivers/adc.h
+++ b/src/main/drivers/adc.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "io.h"
+#include "io_types.h"
 
 typedef enum {
     ADC_BATTERY = 0,
diff --git a/src/main/drivers/adc_impl.h b/src/main/drivers/adc_impl.h
index 146ada62be..c89dc1bf53 100644
--- a/src/main/drivers/adc_impl.h
+++ b/src/main/drivers/adc_impl.h
@@ -17,8 +17,8 @@
 
 #pragma once
 
-#include "io.h"
-#include "rcc.h"
+#include "io_types.h"
+#include "rcc_types.h"
 
 #if defined(STM32F4)
 #define ADC_TAG_MAP_COUNT 16
@@ -65,4 +65,4 @@ extern const adcTagMap_t adcTagMap[ADC_TAG_MAP_COUNT];
 extern adc_config_t adcConfig[ADC_CHANNEL_COUNT];
 extern volatile uint16_t adcValues[ADC_CHANNEL_COUNT];
 
-uint8_t adcChannelByTag(ioTag_t ioTag);
\ No newline at end of file
+uint8_t adcChannelByTag(ioTag_t ioTag);
diff --git a/src/main/drivers/barometer_ms5611.c b/src/main/drivers/barometer_ms5611.c
index 468f86046f..413fe5e980 100644
--- a/src/main/drivers/barometer_ms5611.c
+++ b/src/main/drivers/barometer_ms5611.c
@@ -22,7 +22,6 @@
 
 #include "barometer.h"
 
-#include "gpio.h"
 #include "system.h"
 #include "bus_i2c.h"
 
diff --git a/src/main/drivers/bus_i2c_soft.c b/src/main/drivers/bus_i2c_soft.c
index 104c77c379..42ea8cadc9 100644
--- a/src/main/drivers/bus_i2c_soft.c
+++ b/src/main/drivers/bus_i2c_soft.c
@@ -22,7 +22,7 @@
 
 #include "build_config.h"
 #include "bus_i2c.h"
-#include "drivers/io.h"
+#include "io.h"
 
 // Software I2C driver, using same pins as hardware I2C, with hw i2c module disabled.
 // Can be configured for I2C2 pinout (SCL: PB10, SDA: PB11) or I2C1 pinout (SCL: PB6, SDA: PB7)
diff --git a/src/main/drivers/bus_i2c_stm32f30x.c b/src/main/drivers/bus_i2c_stm32f30x.c
index 9b48aeb76e..3fa55c4512 100644
--- a/src/main/drivers/bus_i2c_stm32f30x.c
+++ b/src/main/drivers/bus_i2c_stm32f30x.c
@@ -20,9 +20,10 @@
 
 #include <platform.h>
 
-#include "gpio.h"
 #include "system.h"
-#include "drivers/io_impl.h"
+#include "io.h"
+#include "io_impl.h"
+#include "rcc.h"
 
 #include "bus_i2c.h"
 
diff --git a/src/main/drivers/compass_ak8963.c b/src/main/drivers/compass_ak8963.c
index 0668fcdd77..d5b9a59dec 100755
--- a/src/main/drivers/compass_ak8963.c
+++ b/src/main/drivers/compass_ak8963.c
@@ -33,9 +33,6 @@
 #include "bus_i2c.h"
 #include "bus_spi.h"
 
-#include "sensors/boardalignment.h"
-#include "sensors/sensors.h"
-
 #include "sensor.h"
 #include "compass.h"
 
diff --git a/src/main/drivers/compass_ak8975.c b/src/main/drivers/compass_ak8975.c
index b6664cb0ab..0647e5f231 100644
--- a/src/main/drivers/compass_ak8975.c
+++ b/src/main/drivers/compass_ak8975.c
@@ -33,8 +33,6 @@
 #include "gpio.h"
 #include "bus_i2c.h"
 
-#include "sensors/sensors.h"
-
 #include "sensor.h"
 #include "compass.h"
 
@@ -157,4 +155,3 @@ bool ak8975Read(int16_t *magData)
     return true;
 }
 #endif
-
diff --git a/src/main/drivers/compass_hmc5883l.c b/src/main/drivers/compass_hmc5883l.c
index caea756bc5..10fa9b3c6d 100644
--- a/src/main/drivers/compass_hmc5883l.c
+++ b/src/main/drivers/compass_hmc5883l.c
@@ -39,8 +39,6 @@
 #include "sensor.h"
 #include "compass.h"
 
-#include "sensors/sensors.h"
-
 #include "compass_hmc5883l.h"
 
 //#define DEBUG_MAG_DATA_READY_INTERRUPT
@@ -274,5 +272,4 @@ bool hmc5883lRead(int16_t *magData)
 
     return true;
 }
-
 #endif
diff --git a/src/main/drivers/compass_hmc5883l.h b/src/main/drivers/compass_hmc5883l.h
index 035a2c936f..e2f71fd28d 100644
--- a/src/main/drivers/compass_hmc5883l.h
+++ b/src/main/drivers/compass_hmc5883l.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "io.h"
+#include "io_types.h"
 
 typedef struct hmc5883Config_s {
     ioTag_t intTag;
diff --git a/src/main/drivers/dma.c b/src/main/drivers/dma.c
index 0ad411312e..7e4942fbe1 100644
--- a/src/main/drivers/dma.c
+++ b/src/main/drivers/dma.c
@@ -21,8 +21,8 @@
 
 #include <platform.h>
 
-#include "drivers/nvic.h"
-#include "drivers/dma.h"
+#include "nvic.h"
+#include "dma.h"
 
 /*
  * DMA descriptors.
diff --git a/src/main/drivers/dma_stm32f4xx.c b/src/main/drivers/dma_stm32f4xx.c
index ec6e7908d3..8372ad0bcb 100644
--- a/src/main/drivers/dma_stm32f4xx.c
+++ b/src/main/drivers/dma_stm32f4xx.c
@@ -21,8 +21,8 @@
 
 #include <platform.h>
 
-#include "drivers/nvic.h"
-#include "drivers/dma.h"
+#include "nvic.h"
+#include "dma.h"
 
 /*
  * DMA descriptors.
diff --git a/src/main/drivers/exti.h b/src/main/drivers/exti.h
index 8071c65e33..adc95f13ab 100644
--- a/src/main/drivers/exti.h
+++ b/src/main/drivers/exti.h
@@ -18,7 +18,7 @@
 
 #pragma once
 
-#include "drivers/io.h"
+#include "io_types.h"
 
 // old EXTI interface, to be replaced
 typedef struct extiConfig_s {
diff --git a/src/main/drivers/io.h b/src/main/drivers/io.h
index d655646282..5afa4abb76 100644
--- a/src/main/drivers/io.h
+++ b/src/main/drivers/io.h
@@ -6,16 +6,7 @@
 #include <platform.h>
 #include "resource.h"
 
-// IO pin identification
-// make sure that ioTag_t can't be assigned into IO_t without warning
-typedef uint8_t ioTag_t;       // packet tag to specify IO pin
-typedef void* IO_t;            // type specifying IO pin. Currently ioRec_t pointer, but this may change
-
-// NONE initializer for ioTag_t variables
-#define IOTAG_NONE ((ioTag_t)0)
-
-// NONE initializer for IO_t variable
-#define IO_NONE ((IO_t)0)
+#include "io_types.h"
 
 // preprocessor is used to convert pinid to requested C data value
 // compile-time error is generated if requested pin is not available (not set in TARGET_IO_PORTx)
@@ -24,19 +15,6 @@ typedef void* IO_t;            // type specifying IO pin. Currently ioRec_t poin
 // expand pinid to to ioTag_t
 #define IO_TAG(pinid) DEFIO_TAG(pinid)
 
-// both ioTag_t and IO_t are guarantied to be zero if pinid is NONE (no pin)
-// this simplifies initialization (globals are zeroed on start) and allows
-//  omitting unused fields in structure initializers.
-// it is also possible to use IO_t and ioTag_t as boolean value
-//   TODO - this may conflict with requirement to generate warning/error on IO_t - ioTag_t assignment
-//   IO_t being pointer is only possibility I know of ..
-
-// pin config handling
-// pin config is packed into ioConfig_t to decrease memory requirements
-// IOCFG_x macros are defined for common combinations for all CPUs; this
-//  helps masking CPU differences
-
-typedef uint8_t ioConfig_t;  // packed IO configuration
 #if defined(STM32F1)
 
 // mode is using only bits 6-2
diff --git a/src/main/drivers/io_types.h b/src/main/drivers/io_types.h
new file mode 100644
index 0000000000..ba80cd3bc7
--- /dev/null
+++ b/src/main/drivers/io_types.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <stdint.h>
+
+// IO pin identification
+// make sure that ioTag_t can't be assigned into IO_t without warning
+typedef uint8_t ioTag_t;       // packet tag to specify IO pin
+typedef void* IO_t;            // type specifying IO pin. Currently ioRec_t pointer, but this may change
+
+// NONE initializer for ioTag_t variables
+#define IOTAG_NONE ((ioTag_t)0)
+
+// NONE initializer for IO_t variable
+#define IO_NONE ((IO_t)0)
+
+// both ioTag_t and IO_t are guarantied to be zero if pinid is NONE (no pin)
+// this simplifies initialization (globals are zeroed on start) and allows
+//  omitting unused fields in structure initializers.
+// it is also possible to use IO_t and ioTag_t as boolean value
+//   TODO - this may conflict with requirement to generate warning/error on IO_t - ioTag_t assignment
+//   IO_t being pointer is only possibility I know of ..
+
+// pin config handling
+// pin config is packed into ioConfig_t to decrease memory requirements
+// IOCFG_x macros are defined for common combinations for all CPUs; this
+//  helps masking CPU differences
+
+typedef uint8_t ioConfig_t;  // packed IO configuration
diff --git a/src/main/drivers/light_ws2811strip.c b/src/main/drivers/light_ws2811strip.c
index 6c8f2bb18a..d9c29af370 100644
--- a/src/main/drivers/light_ws2811strip.c
+++ b/src/main/drivers/light_ws2811strip.c
@@ -36,8 +36,8 @@
 
 #include "common/color.h"
 #include "common/colorconversion.h"
-#include "drivers/dma.h"
-#include "drivers/light_ws2811strip.h"
+#include "dma.h"
+#include "light_ws2811strip.h"
 
 uint8_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
 volatile uint8_t ws2811LedDataTransferInProgress = 0;
diff --git a/src/main/drivers/light_ws2811strip_stm32f10x.c b/src/main/drivers/light_ws2811strip_stm32f10x.c
index 4b588a0c9f..911b7cdc66 100644
--- a/src/main/drivers/light_ws2811strip_stm32f10x.c
+++ b/src/main/drivers/light_ws2811strip_stm32f10x.c
@@ -23,10 +23,11 @@
 #ifdef LED_STRIP
 
 #include "common/color.h"
-#include "drivers/light_ws2811strip.h"
+#include "light_ws2811strip.h"
 #include "nvic.h"
 #include "io.h"
 #include "dma.h"
+#include "rcc.h"
 #include "timer.h"
 
 static IO_t ws2811IO = IO_NONE;
diff --git a/src/main/drivers/light_ws2811strip_stm32f30x.c b/src/main/drivers/light_ws2811strip_stm32f30x.c
index 8379188f99..1fadfb1f03 100644
--- a/src/main/drivers/light_ws2811strip_stm32f30x.c
+++ b/src/main/drivers/light_ws2811strip_stm32f30x.c
@@ -26,7 +26,7 @@
 #include "nvic.h"
 
 #include "common/color.h"
-#include "drivers/light_ws2811strip.h"
+#include "light_ws2811strip.h"
 #include "dma.h"
 #include "rcc.h"
 #include "timer.h"
diff --git a/src/main/drivers/pwm_mapping.h b/src/main/drivers/pwm_mapping.h
index c3d70405ce..1e265d3ffc 100644
--- a/src/main/drivers/pwm_mapping.h
+++ b/src/main/drivers/pwm_mapping.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "timer.h"
+#include "io_types.h"
 
 #if defined(USE_QUAD_MIXER_ONLY)
 #define MAX_PWM_MOTORS  4
@@ -101,10 +101,11 @@ typedef enum {
     PWM_PF_PWM = (1 << 6)
 } pwmPortFlags_e;
 
+struct timerHardware_s;
 typedef struct pwmPortConfiguration_s {
     uint8_t index;
     pwmPortFlags_e flags;
-    const timerHardware_t *timerHardware;
+    const struct timerHardware_s *timerHardware;
 } pwmPortConfiguration_t;
 
 typedef struct pwmIOConfiguration_s {
@@ -145,4 +146,5 @@ extern const uint16_t multiPWM[];
 extern const uint16_t airPPM[];
 extern const uint16_t airPWM[];
 
+pwmIOConfiguration_t *pwmInit(drv_pwm_config_t *init);
 pwmIOConfiguration_t *pwmGetOutputConfiguration(void);
diff --git a/src/main/drivers/pwm_output.c b/src/main/drivers/pwm_output.c
index 8177efa7ee..8b8c5853ce 100644
--- a/src/main/drivers/pwm_output.c
+++ b/src/main/drivers/pwm_output.c
@@ -27,8 +27,6 @@
 #include "io_impl.h"
 #include "timer.h"
 
-#include "flight/failsafe.h" // FIXME dependency into the main code from a driver
-
 #include "pwm_mapping.h"
 
 #include "pwm_output.h"
diff --git a/src/main/drivers/pwm_rx.c b/src/main/drivers/pwm_rx.c
index 1e2b16e4d7..c3bb4cf6c6 100644
--- a/src/main/drivers/pwm_rx.c
+++ b/src/main/drivers/pwm_rx.c
@@ -30,9 +30,10 @@
 #include "system.h"
 
 #include "nvic.h"
-#include "gpio.h"
+#include "io.h"
 #include "timer.h"
 
+#include "pwm_output.h"
 #include "pwm_mapping.h"
 
 #include "pwm_rx.h"
diff --git a/src/main/drivers/rcc.h b/src/main/drivers/rcc.h
index fb04ec7e2c..4dee74ee79 100644
--- a/src/main/drivers/rcc.h
+++ b/src/main/drivers/rcc.h
@@ -1,7 +1,6 @@
 #pragma once
 
-#include "platform.h"
-#include "common/utils.h"
+#include "rcc_types.h"
 
 enum rcc_reg {
     RCC_EMPTY = 0,   // make sure that default value (0) does not enable anything
@@ -17,9 +16,6 @@ enum rcc_reg {
 #define RCC_APB1(periph) RCC_ENCODE(RCC_APB1, RCC_APB1ENR_ ## periph ## EN)
 #define RCC_AHB1(periph) RCC_ENCODE(RCC_AHB1, RCC_AHB1ENR_ ## periph ## EN)
 
-typedef uint8_t rccPeriphTag_t;
-
 void RCC_ClockCmd(rccPeriphTag_t periphTag, FunctionalState NewState);
 void RCC_ResetCmd(rccPeriphTag_t periphTag, FunctionalState NewState);
 
-
diff --git a/src/main/drivers/rcc_types.h b/src/main/drivers/rcc_types.h
new file mode 100644
index 0000000000..1b7d7b9f2f
--- /dev/null
+++ b/src/main/drivers/rcc_types.h
@@ -0,0 +1,4 @@
+#pragma once
+
+typedef uint8_t rccPeriphTag_t;
+
diff --git a/src/main/drivers/serial_usb_vcp.c b/src/main/drivers/serial_usb_vcp.c
index 2c2cebbac6..50c6055ddd 100644
--- a/src/main/drivers/serial_usb_vcp.c
+++ b/src/main/drivers/serial_usb_vcp.c
@@ -22,7 +22,7 @@
 
 #include "build_config.h"
 #include "common/utils.h"
-#include "drivers/io.h"
+#include "io.h"
 
 #include "usb_core.h"
 #ifdef STM32F4
@@ -32,7 +32,7 @@
 #include "hw_config.h"
 #endif
 
-#include "drivers/system.h"
+#include "system.h"
 
 #include "serial.h"
 #include "serial_usb_vcp.h"
diff --git a/src/main/drivers/sound_beeper.h b/src/main/drivers/sound_beeper.h
index ab7a7c3dfc..9caad4f554 100644
--- a/src/main/drivers/sound_beeper.h
+++ b/src/main/drivers/sound_beeper.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "drivers/io.h"
+#include "io_types.h"
 
 #ifdef BEEPER
 #define BEEP_TOGGLE              systemBeepToggle()
diff --git a/src/main/drivers/system.h b/src/main/drivers/system.h
index 08c0835ba5..105a584c44 100644
--- a/src/main/drivers/system.h
+++ b/src/main/drivers/system.h
@@ -67,4 +67,3 @@ void unregisterExtiCallbackHandler(IRQn_Type irqn, extiCallbackHandlerFunc *fn);
 
 extern uint32_t cachedRccCsrValue;
 
-
diff --git a/src/main/drivers/system_stm32f10x.c b/src/main/drivers/system_stm32f10x.c
index bd81852fe0..3e33c545b8 100644
--- a/src/main/drivers/system_stm32f10x.c
+++ b/src/main/drivers/system_stm32f10x.c
@@ -28,7 +28,7 @@
 #define AIRCR_VECTKEY_MASK    ((uint32_t)0x05FA0000)
 
 // from system_stm32f10x.c
-void SetSysClock(void);
+void SetSysClock(bool overclock);
 
 void systemReset(void)
 {
@@ -70,7 +70,7 @@ void systemInit(void)
 {
     checkForBootLoaderRequest();
 
-    SetSysClock();
+    SetSysClock(false);
 
 #ifdef CC3D
     /* Accounts for OP Bootloader, set the Vector Table base address as specified in .ld file */
diff --git a/src/main/drivers/system_stm32f30x.c b/src/main/drivers/system_stm32f30x.c
index fb30936968..16410e658f 100644
--- a/src/main/drivers/system_stm32f30x.c
+++ b/src/main/drivers/system_stm32f30x.c
@@ -26,7 +26,7 @@
 #include "system.h"
 
 #define AIRCR_VECTKEY_MASK    ((uint32_t)0x05FA0000)
-void SetSysClock();
+void SetSysClock(void);
 
 void systemReset(void)
 {
diff --git a/src/main/drivers/system_stm32f4xx.c b/src/main/drivers/system_stm32f4xx.c
index 5c09ebdf6a..8b48f82f5e 100644
--- a/src/main/drivers/system_stm32f4xx.c
+++ b/src/main/drivers/system_stm32f4xx.c
@@ -22,7 +22,7 @@
 #include "platform.h"
 
 #include "accgyro_mpu.h"
-#include "gpio.h"
+#include "exti.h"
 #include "nvic.h"
 #include "system.h"
 
diff --git a/src/main/drivers/timer.c b/src/main/drivers/timer.c
index 15e36cce3f..5051588c99 100755
--- a/src/main/drivers/timer.c
+++ b/src/main/drivers/timer.c
@@ -25,7 +25,7 @@
 
 #include "nvic.h"
 
-#include "gpio.h"
+#include "io.h"
 #include "rcc.h"
 #include "system.h"
 
diff --git a/src/main/drivers/timer.h b/src/main/drivers/timer.h
index 7050bbabda..00410a9c68 100644
--- a/src/main/drivers/timer.h
+++ b/src/main/drivers/timer.h
@@ -17,12 +17,11 @@
 
 #pragma once
 
-#include "io.h"
-#include "rcc.h"
+#include <stdbool.h>
+#include <stdint.h>
 
-#if !defined(USABLE_TIMER_CHANNEL_COUNT)
-#define USABLE_TIMER_CHANNEL_COUNT 14
-#endif
+#include "io_types.h"
+#include "rcc_types.h"
 
 typedef uint16_t captureCompare_t;        // 16 bit on both 103 and 303, just register access must be 32bit sometimes (use timCCR_t)
 
diff --git a/src/main/drivers/timer_stm32f10x.c b/src/main/drivers/timer_stm32f10x.c
index 1a5085e63a..d918b07112 100644
--- a/src/main/drivers/timer_stm32f10x.c
+++ b/src/main/drivers/timer_stm32f10x.c
@@ -5,6 +5,13 @@
   http://www.st.com/software_license_agreement_liberty_v2
 */
 
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "common/utils.h"
+
 #include "stm32f10x.h"
 #include "rcc.h"
 #include "timer.h"
diff --git a/src/main/drivers/timer_stm32f30x.c b/src/main/drivers/timer_stm32f30x.c
index 04069b20c3..871cfb6d78 100644
--- a/src/main/drivers/timer_stm32f30x.c
+++ b/src/main/drivers/timer_stm32f30x.c
@@ -5,6 +5,13 @@
   http://www.st.com/software_license_agreement_liberty_v2
 */
 
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "common/utils.h"
+
 #include "stm32f30x.h"
 #include "rcc.h"
 #include "timer.h"
diff --git a/src/main/drivers/timer_stm32f4xx.c b/src/main/drivers/timer_stm32f4xx.c
index af09f85e1b..750324e94a 100644
--- a/src/main/drivers/timer_stm32f4xx.c
+++ b/src/main/drivers/timer_stm32f4xx.c
@@ -5,9 +5,16 @@
   http://www.st.com/software_license_agreement_liberty_v2
 */
 
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "common/utils.h"
+
 #include "stm32f4xx.h"
-#include "timer.h"
 #include "rcc.h"
+#include "timer.h"
 
 /**
   * @brief  Selects the TIM Output Compare Mode.
diff --git a/src/main/flight/failsafe.h b/src/main/flight/failsafe.h
index 25f9aa98d0..fbe8b68344 100644
--- a/src/main/flight/failsafe.h
+++ b/src/main/flight/failsafe.h
@@ -81,6 +81,8 @@ typedef struct failsafeState_s {
     failsafeRxLinkState_e rxLinkState;
 } failsafeState_t;
 
+struct rxConfig_s;
+void failsafeInit(struct rxConfig_s *intialRxConfig, uint16_t deadband3d_throttle);
 void useFailsafeConfig(failsafeConfig_t *failsafeConfigToUse);
 failsafeConfig_t * getActiveFailsafeConfig(void);
 
diff --git a/src/main/flight/imu.h b/src/main/flight/imu.h
index 4e20ffff7c..e331ac3997 100644
--- a/src/main/flight/imu.h
+++ b/src/main/flight/imu.h
@@ -17,8 +17,6 @@
 
 #pragma once
 
-#include "flight/pid.h"
-
 #define GRAVITY_CMSS    980.665f
 
 extern int16_t throttleAngleCorrection;
@@ -48,7 +46,8 @@ typedef struct imuRuntimeConfig_s {
     uint8_t small_angle;
 } imuRuntimeConfig_t;
 
-void imuConfigure(imuRuntimeConfig_t *initialImuRuntimeConfig, pidProfile_t *initialPidProfile);
+struct pidProfile_s;
+void imuConfigure(imuRuntimeConfig_t *initialImuRuntimeConfig, struct pidProfile_s *initialPidProfile);
 
 void imuUpdateGyroAndAttitude(void);
 void imuUpdateAccelerometer(void);
@@ -61,3 +60,4 @@ void imuTransformVectorBodyToEarth(t_fp_vector * v);
 void imuTransformVectorEarthToBody(t_fp_vector * v);
 
 int16_t imuCalculateHeading(t_fp_vector *vec);
+void imuInit(void);
diff --git a/src/main/flight/mixer.h b/src/main/flight/mixer.h
index 527316c4bb..e2ee918167 100644
--- a/src/main/flight/mixer.h
+++ b/src/main/flight/mixer.h
@@ -235,7 +235,11 @@ void mixerLoadMix(int index, motorMixer_t *customMixers);
 void servoMixerLoadMix(int index, servoMixer_t *customServoMixers);
 void loadCustomServoMixer(void);
 int servoDirection(int servoIndex, int fromChannel);
+void mixerInit(mixerMode_e mixerMode, motorMixer_t *initialCustomMotorMixers, servoMixer_t *initialCustomServoMixers);
+#else
+void mixerInit(mixerMode_e mixerMode, motorMixer_t *initialCustomMixers);
 #endif
+void mixerUsePWMIOConfiguration(void);
 void mixerResetDisarmedMotors(void);
 void mixTable(void);
 void writeMotors(void);
diff --git a/src/main/io/display.h b/src/main/io/display.h
index 6ff3a62004..c8969c7897 100644
--- a/src/main/io/display.h
+++ b/src/main/io/display.h
@@ -21,6 +21,8 @@ typedef enum {
     PAGE_STATUS
 } pageId_e;
 
+struct rxConfig_s;
+void displayInit(struct rxConfig_s *intialRxConfig);
 void updateDisplay(void);
 
 void displaySetPage(pageId_e newPageId);
diff --git a/src/main/io/gps.h b/src/main/io/gps.h
index ff0f3237f1..166821b082 100644
--- a/src/main/io/gps.h
+++ b/src/main/io/gps.h
@@ -132,5 +132,8 @@ typedef struct {
 extern gpsSolutionData_t gpsSol;
 extern gpsStatistics_t   gpsStats;
 
+void gpsPreInit(gpsConfig_t *initialGpsConfig);
+struct serialConfig_s;
+void gpsInit(struct serialConfig_s *serialConfig, gpsConfig_t *initialGpsConfig);
 void gpsThread(void);
 void updateGpsIndicator(uint32_t currentTime);
diff --git a/src/main/io/serial_cli.h b/src/main/io/serial_cli.h
index d54b04cecf..7c8754a3b9 100644
--- a/src/main/io/serial_cli.h
+++ b/src/main/io/serial_cli.h
@@ -15,12 +15,12 @@
  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef CLI_H_
-#define CLI_H_
+#pragma once
 
 extern uint8_t cliMode;
 
+struct serialConfig_s;
+void cliInit(struct serialConfig_s *serialConfig);
 void cliProcess(void);
-bool cliIsActiveOnPort(serialPort_t *serialPort);
-
-#endif /* CLI_H_ */
+struct serialPort_s;
+bool cliIsActiveOnPort(struct serialPort_s *serialPort);
diff --git a/src/main/main.c b/src/main/main.c
index 0e7e470847..0d9018d07d 100644
--- a/src/main/main.c
+++ b/src/main/main.c
@@ -25,6 +25,7 @@
 #include "common/color.h"
 #include "common/atomic.h"
 #include "common/maths.h"
+#include "common/printf.h"
 
 #include "drivers/nvic.h"
 
@@ -33,6 +34,7 @@
 #include "drivers/dma.h"
 #include "drivers/exti.h"
 #include "drivers/gpio.h"
+#include "drivers/io.h"
 #include "drivers/light_led.h"
 #include "drivers/sound_beeper.h"
 #include "drivers/timer.h"
@@ -43,6 +45,7 @@
 #include "drivers/compass.h"
 #include "drivers/pwm_mapping.h"
 #include "drivers/pwm_rx.h"
+#include "drivers/pwm_output.h"
 #include "drivers/adc.h"
 #include "drivers/bus_i2c.h"
 #include "drivers/bus_spi.h"
@@ -55,6 +58,7 @@
 #include "drivers/exti.h"
 
 #include "rx/rx.h"
+#include "rx/spektrum.h"
 
 #include "io/beeper.h"
 #include "io/serial.h"
@@ -66,6 +70,8 @@
 #include "io/ledstrip.h"
 #include "io/display.h"
 #include "io/asyncfatfs/asyncfatfs.h"
+#include "io/serial_msp.h"
+#include "io/serial_cli.h"
 
 #include "scheduler/scheduler.h"
 
@@ -77,6 +83,7 @@
 #include "sensors/battery.h"
 #include "sensors/boardalignment.h"
 #include "sensors/initialisation.h"
+#include "sensors/sonar.h"
 
 #include "telemetry/telemetry.h"
 #include "blackbox/blackbox.h"
@@ -105,27 +112,6 @@ extern uint8_t motorControlEnable;
 serialPort_t *loopbackPort;
 #endif
 
-void printfSupportInit(void);
-void timerInit(void);
-void telemetryInit(void);
-void mspInit();
-void cliInit(serialConfig_t *serialConfig);
-void failsafeInit(rxConfig_t *intialRxConfig, uint16_t deadband3d_throttle);
-pwmIOConfiguration_t *pwmInit(drv_pwm_config_t *init);
-#ifdef USE_SERVOS
-void mixerInit(mixerMode_e mixerMode, motorMixer_t *customMotorMixers, servoMixer_t *customServoMixers);
-#else
-void mixerInit(mixerMode_e mixerMode, motorMixer_t *customMotorMixers);
-#endif
-void mixerUsePWMIOConfiguration(void);
-void rxInit(rxConfig_t *rxConfig, modeActivationCondition_t *modeActivationConditions);
-void gpsPreInit(gpsConfig_t *initialGpsConfig);
-void gpsInit(serialConfig_t *serialConfig, gpsConfig_t *initialGpsConfig);
-void imuInit(void);
-void displayInit(rxConfig_t *intialRxConfig);
-void spektrumBind(rxConfig_t *rxConfig);
-const sonarHcsr04Hardware_t *sonarGetHardwareConfiguration(currentSensor_e currentSensor);
-
 typedef enum {
     SYSTEM_STATE_INITIALISING   = 0,
     SYSTEM_STATE_CONFIG_LOADED  = (1 << 0),
@@ -391,6 +377,7 @@ void init(void)
     adcInit(&adc_params);
 #endif
 
+
     initBoardAlignment(&masterConfig.boardAlignment);
 
 #ifdef DISPLAY
@@ -441,7 +428,7 @@ void init(void)
 
     imuInit();
 
-    mspInit(&masterConfig.serialConfig);
+    mspInit();
 
 #ifdef USE_CLI
     cliInit(&masterConfig.serialConfig);
diff --git a/src/main/rx/rx.h b/src/main/rx/rx.h
index 6af1cb3ffa..5d77922d1d 100644
--- a/src/main/rx/rx.h
+++ b/src/main/rx/rx.h
@@ -141,6 +141,8 @@ typedef struct rxRuntimeConfig_s {
 
 extern rxRuntimeConfig_t rxRuntimeConfig;
 
+struct modeActivationCondition_s;
+void rxInit(rxConfig_t *rxConfig, struct modeActivationCondition_s *modeActivationConditions);
 void useRxConfig(rxConfig_t *rxConfigToUse);
 
 typedef uint16_t (*rcReadRawDataPtr)(rxRuntimeConfig_t *rxRuntimeConfig, uint8_t chan);        // used by receiver driver to return channel data
diff --git a/src/main/rx/spektrum.h b/src/main/rx/spektrum.h
index 10e4056764..23a68b1217 100644
--- a/src/main/rx/spektrum.h
+++ b/src/main/rx/spektrum.h
@@ -21,4 +21,7 @@
 #define SPEKTRUM_SAT_BIND_MAX 10
 
 uint8_t spektrumFrameStatus(void);
-bool spektrumInit(rxConfig_t *rxConfig, rxRuntimeConfig_t *rxRuntimeConfig, rcReadRawDataPtr *callback);
+struct rxConfig_s;
+void spektrumBind(struct rxConfig_s *rxConfig);
+struct rxRuntimeConfig_s;
+bool spektrumInit(struct rxConfig_s *rxConfig, struct rxRuntimeConfig_s *rxRuntimeConfig, rcReadRawDataPtr *callback);
diff --git a/src/main/sensors/initialisation.c b/src/main/sensors/initialisation.c
index ce19be1c86..5475974837 100755
--- a/src/main/sensors/initialisation.c
+++ b/src/main/sensors/initialisation.c
@@ -24,7 +24,7 @@
 
 #include "common/axis.h"
 
-#include "drivers/gpio.h"
+#include "drivers/io.h"
 #include "drivers/system.h"
 #include "drivers/exti.h"
 
diff --git a/src/main/sensors/sonar.h b/src/main/sensors/sonar.h
index e61b65a64c..68138b5804 100644
--- a/src/main/sensors/sonar.h
+++ b/src/main/sensors/sonar.h
@@ -18,7 +18,7 @@
 #pragma once
 
 #include "drivers/sonar_hcsr04.h"
-#include "drivers/sonar.h"
+#include "drivers/rangefinder.h"
 #include "sensors/battery.h"
 
 typedef enum {
@@ -32,7 +32,8 @@ typedef enum {
     SONAR_HCSR04_PINS_PWM,
 } sonarHCSR04Pins_e;
 
-typedef void (*sonarInitFunctionPtr)(sonarRange_t *sonarRange);
+struct sonarRange_s;
+typedef void (*sonarInitFunctionPtr)(struct sonarRange_s *sonarRange);
 typedef void (*sonarUpdateFunctionPtr)(void);
 typedef int32_t (*sonarReadFunctionPtr)(void);
 
diff --git a/src/main/target/ALIENFLIGHTF3/target.c b/src/main/target/ALIENFLIGHTF3/target.c
index 57fc417638..3a151df75b 100644
--- a/src/main/target/ALIENFLIGHTF3/target.c
+++ b/src/main/target/ALIENFLIGHTF3/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM11 | (MAP_TO_PPM_INPUT << 8), // PPM input
diff --git a/src/main/target/CC3D/target.c b/src/main/target/CC3D/target.c
index 4cc13769ea..99d3ab0039 100644
--- a/src/main/target/CC3D/target.c
+++ b/src/main/target/CC3D/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
 #ifdef CC3D_PPM1
diff --git a/src/main/target/CHEBUZZF3/target.c b/src/main/target/CHEBUZZF3/target.c
index 631d83e6aa..c2aca46716 100644
--- a/src/main/target/CHEBUZZF3/target.c
+++ b/src/main/target/CHEBUZZF3/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/CJMCU/target.c b/src/main/target/CJMCU/target.c
index 0f8228559e..3562e3234d 100644
--- a/src/main/target/CJMCU/target.c
+++ b/src/main/target/CJMCU/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8), // PPM input
diff --git a/src/main/target/CJMCU/target.h b/src/main/target/CJMCU/target.h
index 955f69b6f5..59d5d86c59 100644
--- a/src/main/target/CJMCU/target.h
+++ b/src/main/target/CJMCU/target.h
@@ -106,4 +106,5 @@
 #define TARGET_IO_PORTB         0xffff
 #define TARGET_IO_PORTC         (BIT(13)|BIT(14)|BIT(15))
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             (TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4))
diff --git a/src/main/target/COLIBRI_RACE/target.c b/src/main/target/COLIBRI_RACE/target.c
index 15e3b3ec0a..4b0a3250f1 100644
--- a/src/main/target/COLIBRI_RACE/target.c
+++ b/src/main/target/COLIBRI_RACE/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/CRAZEPONYMINI/target.c b/src/main/target/CRAZEPONYMINI/target.c
index 937dd2e025..2875c44fa9 100644
--- a/src/main/target/CRAZEPONYMINI/target.c
+++ b/src/main/target/CRAZEPONYMINI/target.c
@@ -21,6 +21,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM2 | (MAP_TO_MOTOR_OUTPUT << 8), // motor #1 (M2)
diff --git a/src/main/target/CRAZEPONYMINI/target.h b/src/main/target/CRAZEPONYMINI/target.h
index 184adc4fd0..f169f15ae2 100644
--- a/src/main/target/CRAZEPONYMINI/target.h
+++ b/src/main/target/CRAZEPONYMINI/target.h
@@ -84,4 +84,5 @@
 #define TARGET_IO_PORTA         0xffff
 #define TARGET_IO_PORTB         0xffff
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             TIM_N(2)
diff --git a/src/main/target/EUSTM32F103RC/target.c b/src/main/target/EUSTM32F103RC/target.c
index b2a0db9a16..0dc2d66044 100644
--- a/src/main/target/EUSTM32F103RC/target.c
+++ b/src/main/target/EUSTM32F103RC/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/EUSTM32F103RC/target.h b/src/main/target/EUSTM32F103RC/target.h
index 8fd8bddcb8..927dad1070 100644
--- a/src/main/target/EUSTM32F103RC/target.h
+++ b/src/main/target/EUSTM32F103RC/target.h
@@ -110,5 +110,6 @@
 #define TARGET_IO_PORTC         0xffff
 #define TARGET_IO_PORTD         (BIT(0)|BIT(1)|BIT(2))
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             (TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4))
 
diff --git a/src/main/target/FURYF3/target.c b/src/main/target/FURYF3/target.c
index c67b90b621..aad55cfdfb 100755
--- a/src/main/target/FURYF3/target.c
+++ b/src/main/target/FURYF3/target.c
@@ -5,6 +5,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8), // PPM input
diff --git a/src/main/target/FURYF3/target.h b/src/main/target/FURYF3/target.h
index 0ba3a670d6..fd8393524a 100755
--- a/src/main/target/FURYF3/target.h
+++ b/src/main/target/FURYF3/target.h
@@ -146,8 +146,8 @@
 #define USE_I2C
 #define I2C_DEVICE              (I2CDEV_1) // SDA (PB9/AF4), SCL (PB8/AF4)
 
-#define I2C1_SCL                PB8
-#define I2C1_SDA                PB9
+#define I2C1_SCL_PIN            PB8
+#define I2C1_SDA_PIN            PB9
 
 #define BOARD_HAS_VOLTAGE_DIVIDER
 #define USE_ADC
diff --git a/src/main/target/LUX_RACE/target.c b/src/main/target/LUX_RACE/target.c
index 15e3b3ec0a..4b0a3250f1 100644
--- a/src/main/target/LUX_RACE/target.c
+++ b/src/main/target/LUX_RACE/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/MOTOLAB/target.c b/src/main/target/MOTOLAB/target.c
index a89063cc9a..cc898ba834 100644
--- a/src/main/target/MOTOLAB/target.c
+++ b/src/main/target/MOTOLAB/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM9  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/NAZE/target.c b/src/main/target/NAZE/target.c
index 7116b53551..dec8739ba0 100644
--- a/src/main/target/NAZE/target.c
+++ b/src/main/target/NAZE/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/NAZE/target.h b/src/main/target/NAZE/target.h
index 1791f0efb3..e18fec9db6 100644
--- a/src/main/target/NAZE/target.h
+++ b/src/main/target/NAZE/target.h
@@ -220,4 +220,5 @@
 #define TARGET_IO_PORTB         0xffff
 #define TARGET_IO_PORTC         ( BIT(13) | BIT(14) | BIT(15) )
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             ( TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4) )
diff --git a/src/main/target/OLIMEXINO/target.c b/src/main/target/OLIMEXINO/target.c
index ca0f265e79..ec7bcd9f2d 100644
--- a/src/main/target/OLIMEXINO/target.c
+++ b/src/main/target/OLIMEXINO/target.c
@@ -21,6 +21,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/OLIMEXINO/target.h b/src/main/target/OLIMEXINO/target.h
index 9cbbc5c97e..6017370947 100644
--- a/src/main/target/OLIMEXINO/target.h
+++ b/src/main/target/OLIMEXINO/target.h
@@ -95,4 +95,5 @@
 #define TARGET_IO_PORTC         0xffff
 #define TARGET_IO_PORTD         (BIT(2))
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             (TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4))
diff --git a/src/main/target/PORT103R/target.c b/src/main/target/PORT103R/target.c
index 8f21b7cbb7..093fa6ee27 100644
--- a/src/main/target/PORT103R/target.c
+++ b/src/main/target/PORT103R/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/PORT103R/target.h b/src/main/target/PORT103R/target.h
index 6a73cccdf7..bb8abaa98c 100644
--- a/src/main/target/PORT103R/target.h
+++ b/src/main/target/PORT103R/target.h
@@ -128,5 +128,6 @@
 #define TARGET_IO_PORTC         0xffff
 #define TARGET_IO_PORTD         (BIT(0)|BIT(1)|BIT(2))
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS     (TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4))
 
diff --git a/src/main/target/REVO/target.c b/src/main/target/REVO/target.c
index bd7bbd4c25..cdca6f5a94 100644
--- a/src/main/target/REVO/target.c
+++ b/src/main/target/REVO/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/REVO/target.h b/src/main/target/REVO/target.h
index cc8b87f173..d0aa54c7dd 100644
--- a/src/main/target/REVO/target.h
+++ b/src/main/target/REVO/target.h
@@ -158,4 +158,5 @@
 #define TARGET_IO_PORTC 0xffff
 #define TARGET_IO_PORTD 0xffff
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS  ( TIM_N(2) | TIM_N(3) | TIM_N(5) | TIM_N(12) | TIM_N(8) | TIM_N(9))
diff --git a/src/main/target/RMDO/target.c b/src/main/target/RMDO/target.c
index 1bea16f50c..c81e7ff70b 100644
--- a/src/main/target/RMDO/target.c
+++ b/src/main/target/RMDO/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT    << 8),  // PPM input
diff --git a/src/main/target/SPARKY/target.c b/src/main/target/SPARKY/target.c
index 389617278b..20b1f185d3 100644
--- a/src/main/target/SPARKY/target.c
+++ b/src/main/target/SPARKY/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM11 | (MAP_TO_PPM_INPUT << 8), // PPM input
diff --git a/src/main/target/SPRACINGF3/target.c b/src/main/target/SPRACINGF3/target.c
index bf2a06da44..99f79ec9b7 100644
--- a/src/main/target/SPRACINGF3/target.c
+++ b/src/main/target/SPRACINGF3/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT    << 8),  // PPM input
@@ -100,8 +101,8 @@ const timerHardware_t timerHardware[USABLE_TIMER_CHANNEL_COUNT] = {
     { TIM2,  IO_TAG(PA0),  TIM_Channel_1, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH1 - PA0  - *TIM2_CH1
     { TIM2,  IO_TAG(PA1),  TIM_Channel_2, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH2 - PA1  - *TIM2_CH2, TIM15_CH1N
     // Production boards swapped RC_CH3/4 swapped to make it easier to use SerialRX using supplied cables - compared to first prototype.
-    { TIM2,  IO_TAG(PB11), TIM_Channel_4, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH3 - PB11 - *TIM2_CH4, USART3_RX (AF7)
-    { TIM2,  IO_TAG(PB10), TIM_Channel_3, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH4 - PB10 - *TIM2_CH3, USART3_TX (AF7)
+    { TIM2,  IO_TAG(PB11), TIM_Channel_4, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH3 - PB11 - *TIM2_CH4, UART3_RX (AF7)
+    { TIM2,  IO_TAG(PB10), TIM_Channel_3, TIM2_IRQn,               0, IOCFG_AF_PP, GPIO_AF_1 }, // RC_CH4 - PB10 - *TIM2_CH3, UART3_TX (AF7)
     { TIM3,  IO_TAG(PB4),  TIM_Channel_1, TIM3_IRQn,               0, IOCFG_AF_PP, GPIO_AF_2 }, // RC_CH5 - PB4  - *TIM3_CH1
     { TIM3,  IO_TAG(PB5),  TIM_Channel_2, TIM3_IRQn,               0, IOCFG_AF_PP, GPIO_AF_2 }, // RC_CH6 - PB5  - *TIM3_CH2
     { TIM3,  IO_TAG(PB0),  TIM_Channel_3, TIM3_IRQn,               0, IOCFG_AF_PP, GPIO_AF_2 }, // RC_CH7 - PB0  - *TIM3_CH3, TIM1_CH2N, TIM8_CH2N
diff --git a/src/main/target/SPRACINGF3EVO/target.c b/src/main/target/SPRACINGF3EVO/target.c
index f6c60d3797..2b1819210e 100755
--- a/src/main/target/SPRACINGF3EVO/target.c
+++ b/src/main/target/SPRACINGF3EVO/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT    << 8),  // PPM input
diff --git a/src/main/target/STM32F3DISCOVERY/target.c b/src/main/target/STM32F3DISCOVERY/target.c
index 1712bebae2..d2c17db5a2 100644
--- a/src/main/target/STM32F3DISCOVERY/target.c
+++ b/src/main/target/STM32F3DISCOVERY/target.c
@@ -20,6 +20,7 @@
 #include <platform.h>
 #include "drivers/io.h"
 #include "drivers/pwm_mapping.h"
+#include "drivers/timer.h"
 
 const uint16_t multiPPM[] = {
     PWM1  | (MAP_TO_PPM_INPUT << 8),     // PPM input
diff --git a/src/main/target/STM32F3DISCOVERY/target.h b/src/main/target/STM32F3DISCOVERY/target.h
index 6feda121bd..ebafe6a585 100644
--- a/src/main/target/STM32F3DISCOVERY/target.h
+++ b/src/main/target/STM32F3DISCOVERY/target.h
@@ -82,5 +82,6 @@
 #define TARGET_IO_PORTE         0xffff
 #define TARGET_IO_PORTF         0x00ff
 
+#define USABLE_TIMER_CHANNEL_COUNT 14
 #define USED_TIMERS             (TIM_N(1) | TIM_N(2) | TIM_N(3) | TIM_N(4) | TIM_N(8) | TIM_N(16) | TIM_N(17))
 
diff --git a/src/main/target/STM32F3DISCOVERY/target.mk b/src/main/target/STM32F3DISCOVERY/target.mk
index 03dae43122..9c52d2e634 100644
--- a/src/main/target/STM32F3DISCOVERY/target.mk
+++ b/src/main/target/STM32F3DISCOVERY/target.mk
@@ -5,12 +5,13 @@ TARGET_SRC = \
             drivers/accgyro_adxl345.c \
             drivers/accgyro_bma280.c \
             drivers/accgyro_l3gd20.c \
+            drivers/accgyro_l3g4200d.c \
             drivers/accgyro_lsm303dlhc.c \
             drivers/accgyro_mma845x.c \
             drivers/accgyro_mpu.c \
             drivers/accgyro_mpu3050.c \
             drivers/accgyro_mpu6050.c \
-            drivers/accgyro_l3g4200d.c \
+            drivers/accgyro_mpu6500.c \
             drivers/barometer_bmp280.c \
             drivers/barometer_ms5611.c \
             drivers/compass_ak8975.c \
diff --git a/src/main/telemetry/ltm.c b/src/main/telemetry/ltm.c
index 901a355dbf..95b18ae5df 100644
--- a/src/main/telemetry/ltm.c
+++ b/src/main/telemetry/ltm.c
@@ -35,7 +35,7 @@
 
 #include "build_config.h"
 
-#if defined(TELEMETRY) && defined(TELEMETRY_LTM)
+#if defined(TELEMETRY_LTM)
 
 #include "common/maths.h"
 #include "common/axis.h"
@@ -268,6 +268,7 @@ static void ltm_nframe(void)
 }
 #endif
 
+#if defined(GPS)
 static bool ltm_shouldSendXFrame(void)
 {
     static uint16_t lastHDOP = 0;
@@ -279,6 +280,7 @@ static bool ltm_shouldSendXFrame(void)
 
     return false;
 }
+#endif
 
 #define LTM_BIT_AFRAME  (1 << 0)
 #define LTM_BIT_GFRAME  (1 << 1)
diff --git a/src/main/telemetry/telemetry.h b/src/main/telemetry/telemetry.h
index b4585e5fce..b61aa68bd4 100644
--- a/src/main/telemetry/telemetry.h
+++ b/src/main/telemetry/telemetry.h
@@ -46,6 +46,7 @@ typedef struct telemetryConfig_s {
     uint8_t hottAlarmSoundInterval;
 } telemetryConfig_t;
 
+void telemetryInit(void);
 bool telemetryCheckRxPortShared(serialPortConfig_t *portConfig);
 extern serialPort_t *telemetrySharedPort;