diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 6f928f9b0..0d53b7ea3 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -917,27 +917,27 @@ inline int divRoundClosest(const int n, const int d)
 #define calc100to256_16Bits(x) calc100to256(x)
 #define calc100toRESX_16Bits(x) calc100toRESX(x)
 
-inline int calc100to256(register int x)
+inline int calc100to256(int x)
 {
   return divRoundClosest(x*256, 100);
 }
 
-inline int calc100toRESX(register int x)
+inline int calc100toRESX(int x)
 {
   return divRoundClosest(x*RESX, 100);
 }
 
-inline int calc1000toRESX(register int x)
+inline int calc1000toRESX(int x)
 {
   return divRoundClosest(x*RESX, 1000);
 }
 
-inline int calcRESXto1000(register int x)
+inline int calcRESXto1000(int x)
 {
   return divRoundClosest(x*1000, RESX);
 }
 
-inline int calcRESXto100(register int x)
+inline int calcRESXto100(int x)
 {
   return divRoundClosest(x*100, RESX);
 }
diff --git a/radio/src/targets/horus/board.h b/radio/src/targets/horus/board.h
index d65e3763b..b368531a3 100644
--- a/radio/src/targets/horus/board.h
+++ b/radio/src/targets/horus/board.h
@@ -27,6 +27,13 @@
 extern "C" {
 #endif
 
+#if __clang__
+// clang is very picky about the use of "register"
+// Tell clang to ignore the warnings for the following files
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
+#endif
+
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/CMSIS/Device/ST/STM32F4xx/Include/stm32f4xx.h"
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/stm32f4xx_rcc.h"
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/stm32f4xx_gpio.h"
@@ -44,7 +51,12 @@ extern "C" {
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/stm32f4xx_tim.h"
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/stm32f4xx_dma2d.h"
 #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/misc.h"
+#if __clang__
+// Restore warnings about registers
+#pragma clang diagnostic pop
+#endif
 
+    
 #if !defined(SIMU)
 #include "usbd_cdc_core.h"
 #include "usbd_msc_core.h"
diff --git a/radio/src/targets/horus/keys_driver.cpp b/radio/src/targets/horus/keys_driver.cpp
index 0a78d6082..7d9b8635d 100644
--- a/radio/src/targets/horus/keys_driver.cpp
+++ b/radio/src/targets/horus/keys_driver.cpp
@@ -93,7 +93,7 @@ uint8_t keyDown()
 
 void checkRotaryEncoder()
 {
-  register uint32_t newpos = ROTARY_ENCODER_POSITION();
+  uint32_t newpos = ROTARY_ENCODER_POSITION();
   if (newpos != rotencPosition) {
     if ((rotencPosition & 0x01) ^ ((newpos & 0x02) >> 1)) {
       --rotencValue[0];
@@ -108,7 +108,7 @@ void checkRotaryEncoder()
 /* TODO common to ARM */
 void readKeysAndTrims()
 {
-  register uint32_t i;
+  uint32_t i;
 
   uint8_t index = 0;
   uint32_t in = readKeys();
@@ -161,7 +161,7 @@ uint8_t keyState(uint8_t index)
 
 uint32_t switchState(uint8_t index)
 {
-  register uint32_t xxx = 0;
+  uint32_t xxx = 0;
   
   switch (index) {
     ADD_3POS_CASE(A, 0);
diff --git a/radio/src/targets/sky9x/adc_driver.cpp b/radio/src/targets/sky9x/adc_driver.cpp
index a3d735270..c1096b632 100644
--- a/radio/src/targets/sky9x/adc_driver.cpp
+++ b/radio/src/targets/sky9x/adc_driver.cpp
@@ -43,8 +43,8 @@ const char ana_direction[NUMBER_ANALOG] = {1, 1, 0, 1 ,0 ,1 ,0, 0, 0};
 // TRGEN = 0 (software trigger only)
 void adcInit()
 {
-  register Adc *padc ;
-  register uint32_t timer ;
+  Adc *padc ;
+  uint32_t timer ;
 
   timer = ( Master_frequency / (3600000*2) ) << 8 ;
   // Enable peripheral clock ADC = bit 29
@@ -65,9 +65,9 @@ void adcInit()
 // Documented bug, must do them 1 by 1
 void adcSingleRead()
 {
-  register Adc *padc;
-  register uint32_t y;
-  register uint32_t x;
+  Adc *padc;
+  uint32_t y;
+  uint32_t x;
 
   for (uint8_t i=0; i<4; i++)
   padc = ADC;
diff --git a/radio/src/targets/sky9x/audio_driver.cpp b/radio/src/targets/sky9x/audio_driver.cpp
index 35f0b674c..de814b3a8 100644
--- a/radio/src/targets/sky9x/audio_driver.cpp
+++ b/radio/src/targets/sky9x/audio_driver.cpp
@@ -31,8 +31,8 @@ const int8_t volumeScale[VOLUME_LEVEL_MAX+1] =
 
 void setSampleRate(uint32_t frequency)
 {
-  register Tc *ptc ;
-  register uint32_t timer ;
+  Tc *ptc ;
+  uint32_t timer ;
 
   timer = Master_frequency / (8 * frequency) ;		// MCK/8 and 100 000 Hz
   if (timer > 65535)
@@ -50,8 +50,8 @@ void setSampleRate(uint32_t frequency)
 // Start TIMER1 at 100000Hz, used for DACC trigger
 void dacTimerStart()
 {
-  register Tc *ptc ;
-  register uint32_t timer ;
+  Tc *ptc ;
+  uint32_t timer ;
 
 	// Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
   PMC->PMC_PCER0 |= 0x01000000L ;		// Enable peripheral clock to TC1
@@ -78,7 +78,7 @@ void dacInit()
 
   PMC->PMC_PCER0 |= 0x40000000L ;		// Enable peripheral clock to DAC
 
-  register Dacc *dacptr = DACC;
+  Dacc *dacptr = DACC;
 
 #if defined(REVA)
   dacptr->DACC_MR = 0x0B010215L ;                       // 0000 1011 0000 0001 0000 0010 0001 0101
@@ -137,7 +137,7 @@ extern "C" void DAC_IRQHandler()
 // Sound routines
 void audioInit()
 {
-  register Pio *pioptr ;
+  Pio *pioptr ;
 
   dacInit() ;
 
diff --git a/radio/src/targets/sky9x/board.cpp b/radio/src/targets/sky9x/board.cpp
index a48aa463a..b778a6a47 100644
--- a/radio/src/targets/sky9x/board.cpp
+++ b/radio/src/targets/sky9x/board.cpp
@@ -50,7 +50,7 @@ extern "C" void sam_boot( void ) ;
 inline void config_free_pins()
 {
 #if defined(REVA)
-  register Pio * pioptr = PIOA ;
+  Pio * pioptr = PIOA ;
   pioptr->PIO_PER = 0x03800000L ;         // Enable bits A25,24,23
   pioptr->PIO_ODR = 0x03800000L ;         // Set as input
   pioptr->PIO_PUER = 0x03800000L ;        // Enable pullups
@@ -73,7 +73,7 @@ inline void config_free_pins()
 inline void setup_switches()
 {
 #if defined(REVA)
-  register Pio *pioptr = PIOA ;
+  Pio *pioptr = PIOA ;
   pioptr->PIO_PER = 0xF8008184 ;          // Enable bits
   pioptr->PIO_ODR = 0xF8008184 ;          // Set bits input
   pioptr->PIO_PUER = 0xF8008184 ;         // Set bits with pullups
@@ -97,7 +97,7 @@ inline void setup_switches()
 #if !defined(SIMU)
 inline void UART3_Configure(uint32_t baudrate, uint32_t masterClock)
 {
-  register Uart *pUart = BT_USART;
+  Uart *pUart = BT_USART;
 
   /* Configure PIO */
   configure_pins( (PIO_PB2 | PIO_PB3), PIN_PERIPHERAL | PIN_INPUT | PIN_PER_A | PIN_PORTB | PIN_NO_PULLUP ) ;
@@ -139,7 +139,7 @@ void UART3_Stop()
 // This was 6 MHz, we may need to slow it to TIMER_CLOCK2 (MCK/8=4.5 MHz)
 inline void start_timer0()
 {
-  register Tc *ptc ;
+  Tc *ptc ;
 
   // Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
   PMC->PMC_PCER0 |= 0x00800000L ;               // Enable peripheral clock to TC0
@@ -158,8 +158,8 @@ inline void start_timer0()
 // Starts TIMER2 at 200Hz,  commentd out drive of TIOA2 (A26, EXT2)
 inline void start_timer2()
 {
-  register Tc *ptc ;
-  register uint32_t timer ;
+  Tc *ptc ;
+  uint32_t timer ;
 
   // Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
   PMC->PMC_PCER0 |= 0x02000000L ;               // Enable peripheral clock to TC2
@@ -195,7 +195,7 @@ void interrupt5ms()
 
 extern "C" void TC2_IRQHandler()
 {
-  register uint32_t dummy;
+  uint32_t dummy;
 
   /* Clear status bit to acknowledge interrupt */
   dummy = TC0->TC_CHANNEL[2].TC_SR;
@@ -220,8 +220,8 @@ extern "C" void TC2_IRQHandler()
 // For testing, just drive it out with PWM
 void init_pwm()
 {
-  register Pwm *pwmptr ;
-  register uint32_t timer ;
+  Pwm *pwmptr ;
+  uint32_t timer ;
 
   PMC->PMC_PCER0 |= ( 1 << ID_PWM ) ;           // Enable peripheral clock to PWM
 
@@ -229,7 +229,7 @@ void init_pwm()
 
   /* Configure PIO */
 #if defined(REVA)
-  register Pio *pioptr = PIOB ;
+  Pio *pioptr = PIOB ;
   pioptr->PIO_PER = 0x00000020L ;         // Enable bit B5
   pioptr->PIO_ODR = 0x00000020L ;         // set as input
 #else
@@ -299,7 +299,7 @@ void init_pwm()
 
 void configure_pins( uint32_t pins, uint16_t config )
 {
-        register Pio *pioptr ;
+        Pio *pioptr ;
 
         pioptr = PIOA + ( ( config & PIN_PORT_MASK ) >> 6) ;
         if ( config & PIN_PULLUP )
@@ -374,8 +374,8 @@ void opentxBootloader();
 #if !defined(AR9X)
 void i2cInit()
 {
-  register Pio *pioptr;
-  register uint32_t timing;
+  Pio *pioptr;
+  uint32_t timing;
 
   PMC->PMC_PCER0 |= 0x00080000L ;               // Enable peripheral clock to TWI0
 
@@ -410,7 +410,7 @@ void boardInit()
     }
   }
 
-  register Pio *pioptr ;
+  Pio *pioptr ;
 
   ResetReason = RSTC->RSTC_SR;
 
@@ -547,7 +547,7 @@ uint8_t getTemperature()
 
 void setSticksGain(uint8_t gains)
 {
-  register Adc *padc ;
+  Adc *padc ;
   uint32_t gain ;
   uint32_t offset ;
 
diff --git a/radio/src/targets/sky9x/board_lowlevel.c b/radio/src/targets/sky9x/board_lowlevel.c
index d01d18a90..3d01a54ff 100644
--- a/radio/src/targets/sky9x/board_lowlevel.c
+++ b/radio/src/targets/sky9x/board_lowlevel.c
@@ -111,8 +111,8 @@ static uint32_t BOARD_ConfigurePmc(void)
 #undef CLOCK_TIMEOUT
 #define CLOCK_TIMEOUT           0xFFFFFFFF
 
-    register uint32_t timeout = 0 ;
-		register Pmc *pmcptr ;
+    uint32_t timeout = 0 ;
+		Pmc *pmcptr ;
 
 		pmcptr = PMC ;
 
@@ -179,8 +179,8 @@ static uint32_t BOARD_ConfigurePmc(void)
 
 void revert_osc()
 {
-  register uint32_t timeout = 0;
-  register Pmc *pmcptr;
+  uint32_t timeout = 0;
+  Pmc *pmcptr;
 
   pmcptr = PMC;
 
diff --git a/radio/src/targets/sky9x/crt.c b/radio/src/targets/sky9x/crt.c
index a42d12128..a9e8640a1 100644
--- a/radio/src/targets/sky9x/crt.c
+++ b/radio/src/targets/sky9x/crt.c
@@ -1,23 +1,23 @@
-/*
- * Copyright (C) OpenTX
- *
- * Based on code named
- *   th9x - http://code.google.com/p/th9x 
- *   er9x - http://code.google.com/p/er9x
- *   gruvin9x - http://code.google.com/p/gruvin9x
- *
- * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
+/*
+ * Copyright (C) OpenTX
+ *
+ * Based on code named
+ *   th9x - http://code.google.com/p/th9x 
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
 #define __CRT_C__
 
 #include <stdint.h>
@@ -71,9 +71,9 @@ extern uint32_t Master_frequency ;
 void ResetHandler (void)
 {
   {
-  	register uint32_t *pSrc;
-  	register uint32_t *pDest;
-  	register uint32_t m_freq ;
+  	uint32_t *pSrc;
+  	uint32_t *pDest;
+  	uint32_t m_freq ;
    
   	 /*
   	  * Call the SystemInit code from CMSIS interface if available.
diff --git a/radio/src/targets/sky9x/eeprom_driver.cpp b/radio/src/targets/sky9x/eeprom_driver.cpp
index 92d3c120b..2951573f1 100644
--- a/radio/src/targets/sky9x/eeprom_driver.cpp
+++ b/radio/src/targets/sky9x/eeprom_driver.cpp
@@ -28,10 +28,10 @@ uint8_t eepromIsTransferComplete()
   return Spi_complete;
 }
 
-uint32_t eepromTransmitData(register uint8_t *command, register uint8_t *tx, register uint8_t *rx, register uint32_t comlen, register uint32_t count)
+uint32_t eepromTransmitData(uint8_t *command, uint8_t *tx, uint8_t *rx, uint32_t comlen, uint32_t count)
 {
-  register Spi * spiptr = SPI;
-  register uint32_t condition;
+  Spi * spiptr = SPI;
+  uint32_t condition;
   static uint8_t discard_rx_command[4];
 
   if (comlen > 4) {
@@ -76,8 +76,8 @@ uint32_t eepromTransmitData(register uint8_t *command, register uint8_t *tx, reg
 
 uint8_t eepromTransmitByte(uint8_t out, bool skipFirst)
 {
-  register Spi * spiptr = SPI;
-  register uint32_t delay;
+  Spi * spiptr = SPI;
+  uint32_t delay;
 
   spiptr->SPI_CR = 1; // Enable
   (void) spiptr->SPI_RDR; // Dump any rx data
@@ -172,8 +172,8 @@ void eepromBlockErase(uint32_t address)
 // Set clock to 3 MHz, AT25 device is rated to 70MHz, 18MHz would be better
 void eepromInit()
 {
-  register Spi * spiptr = SPI;
-  register uint32_t timer;
+  Spi * spiptr = SPI;
+  uint32_t timer;
 
   PMC->PMC_PCER0 |= 0x00200000L; // Enable peripheral clock to SPI
   /* Configure PIO */
@@ -190,7 +190,7 @@ void eepromInit()
 
 extern "C" void SPI_IRQHandler()
 {
-  register Spi * spiptr = SPI;
+  Spi * spiptr = SPI;
   SPI->SPI_IDR = 0x07FF; // All interrupts off
   spiptr->SPI_CR = 2; // Disable
   (void) spiptr->SPI_RDR; // Dump any rx data
diff --git a/radio/src/targets/sky9x/haptic_driver.cpp b/radio/src/targets/sky9x/haptic_driver.cpp
index 7e1ce448a..f6b50b2e1 100644
--- a/radio/src/targets/sky9x/haptic_driver.cpp
+++ b/radio/src/targets/sky9x/haptic_driver.cpp
@@ -30,7 +30,7 @@ void hapticOff()
 // pwmPercent 0-100
 void hapticOn( uint32_t pwmPercent )
 {
-  register Pwm *pwmptr ;
+  Pwm *pwmptr ;
 
   pwmptr = PWM ;
 
diff --git a/radio/src/targets/sky9x/i2c_driver.cpp b/radio/src/targets/sky9x/i2c_driver.cpp
index 7a4d4c75d..d98520169 100644
--- a/radio/src/targets/sky9x/i2c_driver.cpp
+++ b/radio/src/targets/sky9x/i2c_driver.cpp
@@ -51,7 +51,7 @@ bool i2cInit()
   //Enable Peripheral Clock
   PMC->PMC_PCER0 |= 0x00080000L;
   //Enable TWI PIOs
-  register Pio *pioptr;
+  Pio *pioptr;
   pioptr = PIOA;
   pioptr->PIO_ABCDSR[0] &= ~0x00000018;        // Peripheral A
   pioptr->PIO_ABCDSR[1] &= ~0x00000018;        // Peripheral A
diff --git a/radio/src/targets/sky9x/keys_driver.cpp b/radio/src/targets/sky9x/keys_driver.cpp
index 75c04f49b..9d999d33f 100644
--- a/radio/src/targets/sky9x/keys_driver.cpp
+++ b/radio/src/targets/sky9x/keys_driver.cpp
@@ -32,8 +32,8 @@
 // LCD pins 5 DOWN, 4 RIGHT, 3 LEFT, 1 UP
 uint32_t readKeys()
 {
-  register uint32_t x;
-  register uint32_t result = 0;
+  uint32_t x;
+  uint32_t result = 0;
 
   x = lcdLock ? lcdInputs : PIOC->PIO_PDSR; // 6 LEFT, 5 RIGHT, 4 DOWN, 3 UP ()
   x = ~x;
@@ -73,7 +73,7 @@ uint32_t readKeys()
 
 uint32_t readTrims()
 {
-  register uint32_t result = 0;
+  uint32_t result = 0;
 
   if (~TRIMS_GPIO_REG_LHL & TRIMS_GPIO_PIN_LHL)
     result |= 0x01;
@@ -107,7 +107,7 @@ uint8_t keyDown()
 
 void readKeysAndTrims()
 {
-  register uint32_t i;
+  uint32_t i;
 
 #if ROTARY_ENCODERS > 0
   keys[BTN_REa].input(REA_DOWN());
@@ -135,8 +135,8 @@ uint8_t keyState(uint8_t index)
 
 uint32_t switchState(uint8_t index)
 {
-  register uint32_t a = PIOA->PIO_PDSR;
-  register uint32_t c = PIOC->PIO_PDSR;
+  uint32_t a = PIOA->PIO_PDSR;
+  uint32_t c = PIOC->PIO_PDSR;
 
   uint32_t xxx = 0;
 
diff --git a/radio/src/targets/sky9x/lcd_driver.cpp b/radio/src/targets/sky9x/lcd_driver.cpp
index 2b4957ce3..90f843c73 100644
--- a/radio/src/targets/sky9x/lcd_driver.cpp
+++ b/radio/src/targets/sky9x/lcd_driver.cpp
@@ -71,7 +71,7 @@ const uint8_t Lcd_lookup[] =
 
 void lcdSendCtl(uint8_t val)
 {
-  register Pio *pioptr;
+  Pio *pioptr;
 
 #if defined(REVA)
   pioptr = PIOC;
@@ -112,7 +112,7 @@ void lcdSendCtl(uint8_t val)
 
 void lcdInit()
 {
-  register Pio *pioptr;
+  Pio *pioptr;
   // /home/thus/txt/datasheets/lcd/KS0713.pdf
   // ~/txt/flieger/ST7565RV17.pdf  from http://www.glyn.de/content.asp?wdid=132&sid=
 
@@ -191,7 +191,7 @@ void lcdInit()
 
 void lcdSetRefVolt(uint8_t val)
 {
-  register Pio *pioptr;
+  Pio *pioptr;
   pioptr = PIOC;
 
   // read the inputs, and lock the LCD lines
@@ -221,14 +221,14 @@ void lcdSetRefVolt(uint8_t val)
 
 void lcdRefresh()
 {
-  register Pio *pioptr;
-  register uint8_t *p = displayBuf;
-  register uint32_t y;
-  register uint32_t x;
-  register uint32_t z;
-  register uint32_t ebit;
+  Pio *pioptr;
+  uint8_t *p = displayBuf;
+  uint32_t y;
+  uint32_t x;
+  uint32_t z;
+  uint32_t ebit;
 #if defined(REVA)
-  register uint8_t *lookup;
+  uint8_t *lookup;
   lookup = (uint8_t *) Lcd_lookup;
 #endif
 
diff --git a/radio/src/targets/sky9x/pulses_driver.cpp b/radio/src/targets/sky9x/pulses_driver.cpp
index 057284ef0..340f01526 100644
--- a/radio/src/targets/sky9x/pulses_driver.cpp
+++ b/radio/src/targets/sky9x/pulses_driver.cpp
@@ -22,7 +22,7 @@
 
 void setExternalModulePolarity()
 {
-  register Pwm * pwmptr = PWM;
+  Pwm * pwmptr = PWM;
   pwmptr->PWM_CH_NUM[3].PWM_CDTYUPD = GET_PPM_DELAY(EXTERNAL_MODULE) * 2; // Duty in half uS
   if (GET_PPM_POLARITY(EXTERNAL_MODULE))
     pwmptr->PWM_CH_NUM[3].PWM_CMR &= ~0x00000200; // CPOL
@@ -32,7 +32,7 @@ void setExternalModulePolarity()
 
 void setExtraModulePolarity()
 {
-  register Pwm * pwmptr = PWM;
+  Pwm * pwmptr = PWM;
   pwmptr->PWM_CH_NUM[1].PWM_CDTYUPD = GET_PPM_DELAY(EXTRA_MODULE) * 2; // Duty in half uS
   if (GET_PPM_POLARITY(EXTRA_MODULE))
     pwmptr->PWM_CH_NUM[1].PWM_CMR &= ~0x00000200; // CPOL
@@ -42,7 +42,7 @@ void setExtraModulePolarity()
 
 void module_output_active()
 {
-  register Pio *pioptr = PIOA;
+  Pio *pioptr = PIOA;
   pioptr->PIO_ABCDSR[0] &= ~PIO_PA17;            // Peripheral C
   pioptr->PIO_ABCDSR[1] |= PIO_PA17;             // Peripheral C
   pioptr->PIO_PDR = PIO_PA17;                    // Disable bit A17 Assign to peripheral
@@ -61,7 +61,7 @@ void module_output_active()
 
 void init_main_ppm(uint32_t period, uint32_t out_enable)
 {
-  register Pwm * pwmptr;
+  Pwm * pwmptr;
 
   setupPulsesPPMModule(EXTERNAL_MODULE);
 
@@ -86,7 +86,7 @@ void init_main_ppm(uint32_t period, uint32_t out_enable)
 
 void disable_main_ppm()
 {
-  register Pio * pioptr = PIOA;
+  Pio * pioptr = PIOA;
   pioptr->PIO_PER = PIO_PA17;                                            // Assign A17 to PIO
   PWM->PWM_IDR1 = PWM_IDR1_CHID3;
 }
@@ -95,7 +95,7 @@ void init_second_ppm(uint32_t period)
 {
 #if !defined(REVA)
   // PWM1 for PPM2
-  register Pwm * pwmptr = PWM;
+  Pwm * pwmptr = PWM;
   configure_pins(PIO_PC15, PIN_PERIPHERAL | PIN_INPUT | PIN_PER_B | PIN_PORTC | PIN_NO_PULLUP );
   pwmptr->PWM_CH_NUM[1].PWM_CMR = 0x0000000B;    // CLKB
   if (!GET_PPM_POLARITY(EXTRA_MODULE)) {
@@ -113,7 +113,7 @@ void init_second_ppm(uint32_t period)
 void disable_second_ppm()
 {
 #if !defined(REVA)
-  register Pio * pioptr = PIOC;
+  Pio * pioptr = PIOC;
   pioptr->PIO_PER = PIO_PC15;                                            // Assign C17 to PIO
   PWM->PWM_IDR1 = PWM_IDR1_CHID1;
 #endif
@@ -163,7 +163,7 @@ void disable_ppm(uint32_t port)
 // TD is on PA17, peripheral A
 void init_ssc()
 {
-  register Ssc * sscptr;
+  Ssc * sscptr;
 
   PMC->PMC_PCER0 |= 0x00400000L;               // Enable peripheral clock to SSC
 
@@ -185,8 +185,8 @@ void init_ssc()
 
 void disable_ssc()
 {
-  register Pio *pioptr;
-  register Ssc *sscptr;
+  Pio *pioptr;
+  Ssc *sscptr;
 
   // Revert back to pwm output
   pioptr = PIOA;
@@ -243,7 +243,7 @@ void disable_dsm2(uint32_t port)
 #if !defined(SIMU)
 extern "C" void PWM_IRQHandler(void)
 {
-  register Pwm * pwmptr = PWM;
+  Pwm * pwmptr = PWM;
   uint32_t reason = pwmptr->PWM_ISR1;
   uint32_t period;
 
@@ -266,7 +266,7 @@ extern "C" void PWM_IRQHandler(void)
         }
         else {
           // Kick off serial output here
-          register Ssc * sscptr = SSC;
+          Ssc * sscptr = SSC;
           sscptr->SSC_TPR = CONVERT_PTR_UINT(modulePulsesData[EXTERNAL_MODULE].pxx.pulses);
           sscptr->SSC_TCR = (uint8_t *)modulePulsesData[EXTERNAL_MODULE].pxx.ptr - (uint8_t *)modulePulsesData[EXTERNAL_MODULE].pxx.pulses;
           sscptr->SSC_PTCR = SSC_PTCR_TXTEN; // Start transfers
@@ -290,7 +290,7 @@ extern "C" void PWM_IRQHandler(void)
         }
         else {
           // Kick off serial output here
-          register Ssc * sscptr = SSC;
+          Ssc * sscptr = SSC;
           sscptr->SSC_TPR = CONVERT_PTR_UINT(modulePulsesData[EXTERNAL_MODULE].dsm2.pulses);
           sscptr->SSC_TCR = (uint8_t *)modulePulsesData[EXTERNAL_MODULE].dsm2.ptr - (uint8_t *)modulePulsesData[EXTERNAL_MODULE].dsm2.pulses;
           sscptr->SSC_PTCR = SSC_PTCR_TXTEN; // Start transfers
diff --git a/radio/src/targets/sky9x/rotenc_driver.cpp b/radio/src/targets/sky9x/rotenc_driver.cpp
index 9b5048f51..b4b66f63c 100644
--- a/radio/src/targets/sky9x/rotenc_driver.cpp
+++ b/radio/src/targets/sky9x/rotenc_driver.cpp
@@ -37,7 +37,7 @@ void rotencEnd()
 volatile uint32_t Rotary_position ;
 extern "C" void PIOC_IRQHandler()
 {
-  register uint32_t dummy;
+  uint32_t dummy;
 
   dummy = PIOC->PIO_ISR ;                 // Read and clear status register
   (void) dummy ;                          // Discard value - prevents compiler warning
diff --git a/radio/src/targets/sky9x/serial2_driver.cpp b/radio/src/targets/sky9x/serial2_driver.cpp
index f207ab165..e3243188a 100644
--- a/radio/src/targets/sky9x/serial2_driver.cpp
+++ b/radio/src/targets/sky9x/serial2_driver.cpp
@@ -62,7 +62,7 @@ uint8_t serial2TracesEnabled()
  */
 void SECOND_UART_Configure(uint32_t baudrate, uint32_t masterClock)
 {
-  register Uart *pUart = SECOND_SERIAL_UART;
+  Uart *pUart = SECOND_SERIAL_UART;
 
   /* Configure PIO */
   configure_pins( (PIO_PA9 | PIO_PA10), PIN_PERIPHERAL | PIN_INPUT | PIN_PER_A | PIN_PORTA | PIN_NO_PULLUP ) ;
diff --git a/radio/src/targets/sky9x/telemetry_driver.cpp b/radio/src/targets/sky9x/telemetry_driver.cpp
index b96a52405..d2eedb469 100644
--- a/radio/src/targets/sky9x/telemetry_driver.cpp
+++ b/radio/src/targets/sky9x/telemetry_driver.cpp
@@ -36,7 +36,7 @@ uint16_t DsmRxTimeout;
 // Uses PA5 and PA6 (RXD and TXD)
 void UART2_Configure(uint32_t baudrate, uint32_t masterClock, int mode)
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
 
   // Configure PIO
   configure_pins( (PIO_PA5 | PIO_PA6), PIN_PERIPHERAL | PIN_INPUT | PIN_PER_A | PIN_PORTA | PIN_NO_PULLUP ) ;
@@ -66,7 +66,7 @@ void UART2_Configure(uint32_t baudrate, uint32_t masterClock, int mode)
 
 void UART2_timeout_enable()
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   pUsart->US_CR = US_CR_STTTO ;
   pUsart->US_RTOR = 115 ;               // Bits @ 115200 ~= 1mS
   pUsart->US_IER = US_IER_TIMEOUT ;
@@ -76,7 +76,7 @@ void UART2_timeout_enable()
 
 void UART2_timeout_disable()
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   pUsart->US_RTOR = 0 ;
   pUsart->US_IDR = US_IDR_TIMEOUT ;
   NVIC_DisableIRQ(USART0_IRQn);
@@ -84,14 +84,14 @@ void UART2_timeout_disable()
 
 extern "C" void USART0_IRQHandler()
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   pUsart->US_CR = US_CR_STTTO ;         // Clears timeout bit
   DsmRxTimeout = 1;
 }
 
 void startPdcUsartReceive()
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   TelemetryInBuffer.outPtr = TelemetryInBuffer.fifo ;
 #ifndef SIMU
   pUsart->US_RPR = (uint32_t)TelemetryInBuffer.fifo ;
@@ -105,7 +105,7 @@ void startPdcUsartReceive()
 void rxPdcUsart( void (*pChProcess)(uint8_t x) )
 {
 #if !defined(SIMU)
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   uint8_t *ptr ;
   uint8_t *endPtr ;
 
@@ -137,7 +137,7 @@ void rxPdcUsart( void (*pChProcess)(uint8_t x) )
 
 uint32_t txPdcUsart(uint8_t *buffer, uint32_t size)
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
 
   if ( pUsart->US_TNCR == 0 )
   {
@@ -153,7 +153,7 @@ uint32_t txPdcUsart(uint8_t *buffer, uint32_t size)
 
 uint32_t telemetryTransmitPending()
 {
-  register Usart *pUsart = SECOND_USART;
+  Usart *pUsart = SECOND_USART;
   uint32_t x ;
 
   __disable_irq() ;
diff --git a/radio/src/targets/sky9x/trainer_driver.cpp b/radio/src/targets/sky9x/trainer_driver.cpp
index 5cba603df..151be4b30 100644
--- a/radio/src/targets/sky9x/trainer_driver.cpp
+++ b/radio/src/targets/sky9x/trainer_driver.cpp
@@ -23,7 +23,7 @@
 // Start TIMER3 for input capture
 inline void start_timer3()
 {
-  register Tc *ptc ;
+  Tc *ptc ;
 
   // Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
   PMC->PMC_PCER0 |= 0x04000000L ;               // Enable peripheral clock to TC3
@@ -45,8 +45,8 @@ inline void start_timer3()
 // Start Timer4 to provide 0.5uS clock for input capture
 void start_timer4()
 {
-  register Tc *ptc ;
-  register uint32_t timer ;
+  Tc *ptc ;
+  uint32_t timer ;
 
   timer = Master_frequency / (2*2000000) ;                // MCK/2 and 2MHz
 
diff --git a/radio/src/targets/taranis/audio_driver.cpp b/radio/src/targets/taranis/audio_driver.cpp
index e50409efc..d30ffc4ee 100644
--- a/radio/src/targets/taranis/audio_driver.cpp
+++ b/radio/src/targets/taranis/audio_driver.cpp
@@ -25,7 +25,7 @@ const AudioBuffer * nextBuffer = 0;
 
 void setSampleRate(uint32_t frequency)
 {
-  register uint32_t timer = (PERI1_FREQUENCY * TIMER_MULT_APB1) / frequency - 1 ;         // MCK/8 and 100 000 Hz
+  uint32_t timer = (PERI1_FREQUENCY * TIMER_MULT_APB1) / frequency - 1 ;         // MCK/8 and 100 000 Hz
 
   AUDIO_TIMER->CR1 &= ~TIM_CR1_CEN ;
   AUDIO_TIMER->CNT = 0 ;
diff --git a/radio/src/targets/taranis/board.h b/radio/src/targets/taranis/board.h
index f079f176b..01052a69f 100644
--- a/radio/src/targets/taranis/board.h
+++ b/radio/src/targets/taranis/board.h
@@ -27,6 +27,13 @@
 extern "C" {
 #endif
 
+#if __clang__
+// clang is very picky about the use of "register"
+// tell it to ignore for the STM32 includes instead of modyfing the orginal files
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
+#endif
+
 #if defined(PCBX9E)
   #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/CMSIS/Device/ST/STM32F4xx/Include/stm32f4xx.h"
   #include "STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries/STM32F4xx_StdPeriph_Driver/inc/stm32f4xx_rcc.h"
@@ -59,6 +66,11 @@ extern "C" {
   #include "STM32F2xx_StdPeriph_Lib_V1.1.0/Libraries/STM32F2xx_StdPeriph_Driver/inc/misc.h"
 #endif
 
+#if __clang__
+// Restore warnings about registers
+#pragma clang diagnostic pop
+#endif
+
 #if !defined(SIMU)
   #include "usbd_cdc_core.h"
   #include "usbd_msc_core.h"
diff --git a/radio/src/targets/taranis/keys_driver.cpp b/radio/src/targets/taranis/keys_driver.cpp
index 59e73b6b9..f4c1b47f4 100644
--- a/radio/src/targets/taranis/keys_driver.cpp
+++ b/radio/src/targets/taranis/keys_driver.cpp
@@ -88,7 +88,7 @@ uint8_t keyDown()
 #if defined(ROTARY_ENCODER_NAVIGATION)
 void checkRotaryEncoder()
 {
-  register uint32_t newpos = ROTARY_ENCODER_POSITION();
+  uint32_t newpos = ROTARY_ENCODER_POSITION();
   if (newpos != rotencPosition) {
     if ((rotencPosition & 0x01) ^ ((newpos & 0x02) >> 1)) {
       --rotencValue[0];
@@ -168,7 +168,7 @@ uint8_t keyState(uint8_t index)
 
 uint32_t switchState(uint8_t index)
 {
-  register uint32_t xxx = 0;
+  uint32_t xxx = 0;
   
   switch (index) {
     ADD_3POS_CASE(A, 0);