diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
index e67c07102e..35a6995038 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
@@ -100,9 +100,10 @@ LoopFillZerobss:
 /* Call the clock system intitialization function.*/
   bl  SystemInit
 /* Call static constructors */
-    bl __libc_init_array
+  //bl __libc_init_array
 /* Call the application's entry point.*/
-  bl  main
+  //bl  main
+  bl _start
 
 LoopForever:
     b LoopForever
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
index e67c07102e..688e623060 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32L0/TARGET_NUCLEO_L053R8/TOOLCHAIN_GCC_ARM/startup_stm32l053xx.s
@@ -100,12 +100,13 @@ LoopFillZerobss:
 /* Call the clock system intitialization function.*/
   bl  SystemInit
 /* Call static constructors */
-    bl __libc_init_array
+  //bl __libc_init_array
 /* Call the application's entry point.*/
-  bl  main
+  //bl  main
+  bl _start
 
 LoopForever:
-    b LoopForever
+  b LoopForever
 
 
 .size  Reset_Handler, .-Reset_Handler
diff --git a/libraries/mbed/targets/hal/TARGET_STM/TARGET_DISCO_L053C8/PeripheralNames.h b/libraries/mbed/targets/hal/TARGET_STM/TARGET_DISCO_L053C8/PeripheralNames.h
index 2a26ecb449..8761532795 100644
--- a/libraries/mbed/targets/hal/TARGET_STM/TARGET_DISCO_L053C8/PeripheralNames.h
+++ b/libraries/mbed/targets/hal/TARGET_STM/TARGET_DISCO_L053C8/PeripheralNames.h
@@ -50,8 +50,8 @@ typedef enum {
     LPUART_1 = (int)LPUART1_BASE
 } UARTName;
 
-#define STDIO_UART_TX  PA_2
-#define STDIO_UART_RX  PA_3
+#define STDIO_UART_TX  PA_9
+#define STDIO_UART_RX  PA_10
 #define STDIO_UART     UART_2
 
 typedef enum {
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
index c2b5baa475..542bccf0b0 100755
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
@@ -286,6 +286,9 @@ osThreadDef_t os_thread_def_main = {(os_pthread)main, osPriorityNormal, 0, NULL}
 #elif defined(TARGET_STM32F429ZI)
 #define INITIAL_SP            (0x20030000UL)
 
+#elif defined(TARGET_STM32L053R8) || defined(TARGET_STM32L053C8)
+#define INITIAL_SP            (0x20002000UL)
+
 #else
 #error "no target defined"
 
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
index 68a03c226e..d3f0452c2a 100755
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
@@ -55,7 +55,7 @@
 #    define OS_TASKCNT         14
 #  elif defined(TARGET_LPC11U24) || defined(TARGET_LPC11U35_401)  || defined(TARGET_LPC11U35_501) || defined(TARGET_LPCCAPPUCCINO) || defined(TARGET_LPC1114) \
    || defined(TARGET_LPC812)   || defined(TARGET_KL25Z)         || defined(TARGET_KL05Z)        || defined(TARGET_STM32F100RB)  || defined(TARGET_STM32F051R8) \
-   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8) || defined(TARGET_STM32F334R8) || defined(TARGET_STM32F334C8)
+   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8) || defined(TARGET_STM32F334R8) || defined(TARGET_STM32F334C8) || defined(TARGET_STM32L053R8) || defined(TARGET_STM32L053C8)
 #    define OS_TASKCNT         6
 #  else
 #    error "no target defined"
@@ -70,7 +70,7 @@
 #      define OS_SCHEDULERSTKSIZE    256
 #  elif defined(TARGET_LPC11U24) || defined(TARGET_LPC11U35_401)  || defined(TARGET_LPC11U35_501) || defined(TARGET_LPCCAPPUCCINO)  || defined(TARGET_LPC1114) \
    || defined(TARGET_LPC812)   || defined(TARGET_KL25Z)         || defined(TARGET_KL05Z)        || defined(TARGET_STM32F100RB)  || defined(TARGET_STM32F051R8) \
-   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8)
+   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8) || defined(TARGET_STM32L053R8) || defined(TARGET_STM32L053C8)
 #      define OS_SCHEDULERSTKSIZE    128
 #  elif defined(TARGET_STM32F334R8) || defined(TARGET_STM32F334C8)
 #      define OS_SCHEDULERSTKSIZE    112
@@ -160,6 +160,9 @@
 #elif defined(TARGET_STM32F302R8)
 #    define OS_CLOCK       64000000
 
+#elif defined(TARGET_STM32L053R8) || defined(TARGET_STM32L053C8)
+#    define OS_CLOCK       32000000
+
 #  else
 #    error "no target defined"
 #  endif
diff --git a/workspace_tools/tests.py b/workspace_tools/tests.py
index 0ae014d048..5c5d448d91 100644
--- a/workspace_tools/tests.py
+++ b/workspace_tools/tests.py
@@ -583,7 +583,7 @@ TESTS = [
         "duration": 15,
         "automated": True,
         "host_test": "wait_us_auto",
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_2", "description": "Mutex resource lock",
@@ -591,7 +591,7 @@ TESTS = [
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "duration": 20,
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_3", "description": "Semaphore resource lock",
@@ -599,28 +599,28 @@ TESTS = [
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "duration": 20,
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_4", "description": "Signals messaging",
         "source_dir": join(TEST_DIR, "rtos", "mbed", "signals"),
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_5", "description": "Queue messaging",
         "source_dir": join(TEST_DIR, "rtos", "mbed", "queue"),
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_6", "description": "Mail messaging",
         "source_dir": join(TEST_DIR, "rtos", "mbed", "mail"),
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_7", "description": "Timer",
@@ -629,14 +629,14 @@ TESTS = [
         "duration": 15,
         "automated": True,
         "host_test": "wait_us_auto",
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_8", "description": "ISR (Queue)",
         "source_dir": join(TEST_DIR, "rtos", "mbed", "isr"),
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, TEST_MBED_LIB],
         "automated": True,
-        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8"],
+        "mcu": ["LPC1768", "LPC1549", "LPC11U24", "LPC812", "KL25Z", "KL05Z", "K64F", "KL46Z", "RZ_A1H", "DISCO_F407VG", "DISCO_F429ZI", "NUCLEO_F411RE", "NUCLEO_F401RE", "NUCLEO_F334R8", "DISCO_F334C8", "NUCLEO_F302R8", "NUCLEO_L053R8", "DISCO_L053C8"],
     },
     {
         "id": "RTOS_9", "description": "SD File write-read",