diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_DISCO_F051R8/system_stm32f0xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_DISCO_F051R8/system_stm32f0xx.c
index b20d91c33b..164d05f195 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_DISCO_F051R8/system_stm32f0xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_DISCO_F051R8/system_stm32f0xx.c
@@ -209,6 +209,7 @@ void SystemInit(void)
   RCC->CIR = 0x00000000;
 
   /* Configure the Cube driver */
+  SystemCoreClock = 8000000; // At this stage the HSI is used as system clock
   HAL_Init();
 
   /* Configure the System clock source, PLL Multiplier and Divider factors,
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F030R8/system_stm32f0xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F030R8/system_stm32f0xx.c
index b2fc901df2..5b7227f3c8 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F030R8/system_stm32f0xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F030R8/system_stm32f0xx.c
@@ -226,6 +226,7 @@ void SystemInit(void)
   RCC->CIR = 0x00000000;
 
   /* Configure the Cube driver */
+  SystemCoreClock = 8000000; // At this stage the HSI is used as system clock
   HAL_Init();
 
   /* Configure the System clock source, PLL Multiplier and Divider factors,
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_DISCO_F100RB/system_stm32f1xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_DISCO_F100RB/system_stm32f1xx.c
index 937b24e597..abbe81c0f0 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_DISCO_F100RB/system_stm32f1xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_DISCO_F100RB/system_stm32f1xx.c
@@ -159,7 +159,7 @@
   uint32_t SystemCoreClock         = 72000000;        /*!< System Clock Frequency (Core Clock) */
 #endif
 
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 /**
   * @}
   */
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_NUCLEO_F103RB/system_stm32f1xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_NUCLEO_F103RB/system_stm32f1xx.c
index 5073ffc87c..196ddfff57 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_NUCLEO_F103RB/system_stm32f1xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F1/TARGET_NUCLEO_F103RB/system_stm32f1xx.c
@@ -161,7 +161,7 @@
   uint32_t SystemCoreClock         = 72000000;        /*!< System Clock Frequency (Core Clock) */
 #endif
 
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 /**
   * @}
   */
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/stm32f30x_rcc.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/stm32f30x_rcc.c
index 3b8f7b6f32..d70377b7d7 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/stm32f30x_rcc.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/stm32f30x_rcc.c
@@ -141,8 +141,8 @@
 
 /* Private macro -------------------------------------------------------------*/
 /* Private variables ---------------------------------------------------------*/
-static __I uint8_t APBAHBPrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};
-static __I uint16_t ADCPrescTable[16] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256, 0, 0, 0, 0 };
+const uint8_t APBAHBPrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint16_t ADCPrescTable[16] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256, 0, 0, 0, 0 };
 
 /* Private function prototypes -----------------------------------------------*/
 /* Private functions ---------------------------------------------------------*/
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/system_stm32f30x.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/system_stm32f30x.c
index fb191f7aa8..5741c6da81 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/system_stm32f30x.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3XX/system_stm32f30x.c
@@ -143,7 +143,7 @@
 
 uint32_t SystemCoreClock = 64000000; /* Default with HSI. Will be updated if HSE is used */
 
-__I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_DISCO_F429ZI/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_DISCO_F429ZI/system_stm32f4xx.c
index c935079912..793c597be4 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_DISCO_F429ZI/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_DISCO_F429ZI/system_stm32f4xx.c
@@ -155,7 +155,7 @@
                variable is updated automatically.
   */
   uint32_t SystemCoreClock = 168000000;
-  __IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_DRAGONFLY_F411RE/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_DRAGONFLY_F411RE/system_stm32f4xx.c
index 47507ff930..bbe76cd827 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_DRAGONFLY_F411RE/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_DRAGONFLY_F411RE/system_stm32f4xx.c
@@ -158,7 +158,7 @@
                variable is updated automatically.
   */
 uint32_t SystemCoreClock = 16000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_MDOT_F411RE/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_MDOT_F411RE/system_stm32f4xx.c
index 036582380a..2a2ff56b73 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_MDOT_F411RE/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_MTS_MDOT_F411RE/system_stm32f4xx.c
@@ -163,7 +163,7 @@
                variable is updated automatically.
   */
 uint32_t SystemCoreClock = 16000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_NUCLEO_F411RE/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_NUCLEO_F411RE/system_stm32f4xx.c
index efb6464a73..4f4a6339c7 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_NUCLEO_F411RE/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_NUCLEO_F411RE/system_stm32f4xx.c
@@ -157,7 +157,7 @@
                variable is updated automatically.
   */
 uint32_t SystemCoreClock = 16000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_UBLOX_C029/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_UBLOX_C029/system_stm32f4xx.c
index efb6464a73..4f4a6339c7 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_UBLOX_C029/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_UBLOX_C029/system_stm32f4xx.c
@@ -157,7 +157,7 @@
                variable is updated automatically.
   */
 uint32_t SystemCoreClock = 16000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/stm32f4xx_hal_rcc.h b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/stm32f4xx_hal_rcc.h
index 3164db2057..fa720c9474 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/stm32f4xx_hal_rcc.h
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/stm32f4xx_hal_rcc.h
@@ -190,7 +190,7 @@ typedef struct
 
 
 #define DBP_TIMEOUT_VALUE          ((uint32_t)100)
-#define LSE_TIMEOUT_VALUE          ((uint32_t)600)
+#define LSE_TIMEOUT_VALUE          ((uint32_t)5000)
 /**
   * @}
   */
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4XX/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4XX/system_stm32f4xx.c
index 9e0004e7bf..02eb8f81df 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4XX/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4XX/system_stm32f4xx.c
@@ -184,7 +184,7 @@
 
   uint32_t SystemCoreClock = 168000000;
 
-  __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/system_stm32l0xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/system_stm32l0xx.c
index 2c7167a6a7..f2a95c6667 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/system_stm32l0xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/system_stm32l0xx.c
@@ -145,9 +145,9 @@
                is no need to call the 2 first functions listed above, since SystemCoreClock
                variable is updated automatically.
   */
-  uint32_t SystemCoreClock = 32000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
-__IO const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
+uint32_t SystemCoreClock = 32000000;
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/system_stm32l0xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/system_stm32l0xx.c
index 2c7167a6a7..f2a95c6667 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/system_stm32l0xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/system_stm32l0xx.c
@@ -145,9 +145,9 @@
                is no need to call the 2 first functions listed above, since SystemCoreClock
                variable is updated automatically.
   */
-  uint32_t SystemCoreClock = 32000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
-__IO const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
+uint32_t SystemCoreClock = 32000000;
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L073RZ/system_stm32l0xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L073RZ/system_stm32l0xx.c
index 2c7167a6a7..f2a95c6667 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L073RZ/system_stm32l0xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L073RZ/system_stm32l0xx.c
@@ -145,9 +145,9 @@
                is no need to call the 2 first functions listed above, since SystemCoreClock
                variable is updated automatically.
   */
-  uint32_t SystemCoreClock = 32000000;
-__IO const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
-__IO const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
+uint32_t SystemCoreClock = 32000000;
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_conf.h b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_conf.h
index e769428483..b68cdd89e1 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_conf.h
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_conf.h
@@ -123,7 +123,7 @@
 
    
 #if !defined  (LSE_STARTUP_TIMEOUT)
-  #define LSE_STARTUP_TIMEOUT    ((uint32_t)500)   /*!< Time out for LSE start up, in ms */
+  #define LSE_STARTUP_TIMEOUT    ((uint32_t)5000)   /*!< Time out for LSE start up, in ms */
 #endif /* HSE_STARTUP_TIMEOUT */
 
    
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_rcc.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_rcc.c
index 01a586c3f7..f48f17eb5a 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_rcc.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/stm32l0xx_hal_rcc.c
@@ -118,8 +118,8 @@
 /** @defgroup RCC_Private_Vatiables RCC Private Data
   * @{
   */ 
-static __IO const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
-static __IO const uint8_t APBAHBPrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
+const uint8_t APBAHBPrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};
 
 /**
   * @}
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L1/stm32l1xx_hal_conf.h b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L1/stm32l1xx_hal_conf.h
index f085833f52..81c5571b5f 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L1/stm32l1xx_hal_conf.h
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L1/stm32l1xx_hal_conf.h
@@ -122,7 +122,7 @@
 
    
 #if !defined  (LSE_STARTUP_TIMEOUT)
-  #define LSE_STARTUP_TIMEOUT    ((uint32_t)500)   /*!< Time out for LSE start up, in ms */
+  #define LSE_STARTUP_TIMEOUT    ((uint32_t)5000)   /*!< Time out for LSE start up, in ms */
 #endif /* HSE_STARTUP_TIMEOUT */