diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.c
index fb191f7aa8..c072384964 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.c
@@ -153,8 +153,6 @@ __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}
   * @{
   */
 
-void SetSysClock(void);
-
 #if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0)
 uint8_t SetSysClock_PLL_HSE(uint8_t bypass);
 #endif
@@ -208,10 +206,6 @@ void SystemInit(void)
   /* Disable all interrupts */
   RCC->CIR = 0x00000000;
 
-  /* Configure the System clock source, PLL Multiplier and Divider factors, 
-     AHB/APBx prescalers and Flash settings */
-  SetSysClock();
-
   /* Configure the Vector Table location add offset address ------------------*/
 #ifdef VECT_TAB_SRAM
   SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.h b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.h
index e624e7e476..dc47b3b53f 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.h
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F302R8/system_stm32f30x.h
@@ -65,6 +65,7 @@ extern uint32_t SystemCoreClock;          /*!< System Clock Frequency (Core Cloc
   
 extern void SystemInit(void);
 extern void SystemCoreClockUpdate(void);
+extern void SetSysClock(void);
 
 /**
   * @}
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/analogin_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/analogin_api.c
index 1733895d99..f0467de01f 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/analogin_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/analogin_api.c
@@ -26,10 +26,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "analogin_api.h"
-#include "wait_api.h"
 
 #if DEVICE_ANALOGIN
 
+#include "wait_api.h"
 #include "cmsis.h"
 #include "pinmap.h"
 #include "error.h"
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/gpio_irq_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/gpio_irq_api.c
index f729c93d81..9bdac95a88 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/gpio_irq_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/gpio_irq_api.c
@@ -29,7 +29,6 @@
  */
 #include <stddef.h>
 #include "cmsis.h"
-
 #include "gpio_irq_api.h"
 #include "pinmap.h"
 #include "error.h"
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c
index c6e24a6e91..7a2c93962d 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c
@@ -100,7 +100,7 @@ void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
 void i2c_frequency(i2c_t *obj, int hz) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2C_InitTypeDef I2C_InitStructure;
-    uint32_t tim;
+    uint32_t tim = 0;
 
     // Disable the Fast Mode Plus capability
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE); // Enable SYSCFG clock
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/mbed_overrides.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/mbed_overrides.c
index c0218bb69c..699c5ad678 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/mbed_overrides.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/mbed_overrides.c
@@ -25,11 +25,14 @@
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-
-extern void SystemCoreClockUpdate(void); 
+#include "cmsis.h"
 
 // This function is called after RAM initialization and before main.
 void mbed_sdk_init() {
+    /* Configure the System clock source, PLL Multiplier and Divider factors,
+     AHB/APBx prescalers and Flash settings */
+    SetSysClock();
+
     // Update the SystemCoreClock variable.
     SystemCoreClockUpdate();
 }
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/pwmout_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/pwmout_api.c
index 1d83cdb6e2..a371e8ee15 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/pwmout_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/pwmout_api.c
@@ -29,6 +29,8 @@
  */
 #include "pwmout_api.h"
 
+#if DEVICE_PWMOUT
+
 #include "cmsis.h"
 #include "pinmap.h"
 #include "error.h"
@@ -275,3 +277,5 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
     float value = (float)us / (float)obj->period;
     pwmout_write(obj, value);
 }
+
+#endif
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/rtc_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/rtc_api.c
index 76720b00f4..3964ac58d3 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/rtc_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/rtc_api.c
@@ -29,6 +29,8 @@
  */
 #include "rtc_api.h"
 
+#if DEVICE_RTC
+
 static int rtc_inited = 0;
 
 void rtc_init(void) {
@@ -136,3 +138,5 @@ void rtc_write(time_t t) {
     RTC_SetTime(RTC_Format_BIN, &timeStruct);
     PWR_BackupAccessCmd(DISABLE); // Disable access to RTC
 }
+
+#endif
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/serial_api.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/serial_api.c
index b7a8181240..89907255f5 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/serial_api.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/serial_api.c
@@ -28,6 +28,9 @@
  *******************************************************************************
  */
 #include "serial_api.h"
+
+#if DEVICE_SERIAL
+
 #include "cmsis.h"
 #include "pinmap.h"
 #include "error.h"
@@ -309,3 +312,5 @@ void serial_break_clear(serial_t *obj) {
     USART_RequestCmd(usart, USART_Request_SBKRQ, DISABLE);
     USART_ClearFlag(usart, USART_FLAG_SBK);
 }
+
+#endif
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/sleep.c b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/sleep.c
index 2ce5b2ecf9..4d08154151 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/sleep.c
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/sleep.c
@@ -28,10 +28,10 @@
  *******************************************************************************
  */
 #include "sleep_api.h"
-#include "cmsis.h"
 
-// This function is in the system_stm32f30x.c file
-extern void SetSysClock(void);
+#if DEVICE_SLEEP
+
+#include "cmsis.h"
 
 // MCU SLEEP mode
 void sleep(void) {
@@ -53,3 +53,5 @@ void deepsleep(void) {
     // After wake-up from STOP reconfigure the PLL
     SetSysClock();
 }
+
+#endif