diff --git a/drivers/source/FlashIAP.cpp b/drivers/source/FlashIAP.cpp
index 71565b80b0..60d48344ca 100644
--- a/drivers/source/FlashIAP.cpp
+++ b/drivers/source/FlashIAP.cpp
@@ -46,7 +46,7 @@ static inline bool is_aligned(uint32_t number, uint32_t alignment)
     }
 }
 
-FlashIAP::FlashIAP()
+FlashIAP::FlashIAP() : _page_buf(nullptr)
 {
 
 }
diff --git a/drivers/source/Ticker.cpp b/drivers/source/Ticker.cpp
index fada56cf64..12a2d2ea60 100644
--- a/drivers/source/Ticker.cpp
+++ b/drivers/source/Ticker.cpp
@@ -24,12 +24,12 @@
 
 namespace mbed {
 
-Ticker::Ticker() : TimerEvent(), _function(0), _lock_deepsleep(true)
+Ticker::Ticker() : TimerEvent(), _delay(0), _function(0), _lock_deepsleep(true)
 {
 }
 
 // When low power ticker is in use, then do not disable deep sleep.
-Ticker::Ticker(const ticker_data_t *data) : TimerEvent(data), _function(0), _lock_deepsleep(!data->interface->runs_in_deep_sleep)
+Ticker::Ticker(const ticker_data_t *data) : TimerEvent(data), _delay(0), _function(0), _lock_deepsleep(!data->interface->runs_in_deep_sleep)
 {
 }
 
diff --git a/platform/ATCmdParser.h b/platform/ATCmdParser.h
index 36ffd8752b..d9a6e98543 100644
--- a/platform/ATCmdParser.h
+++ b/platform/ATCmdParser.h
@@ -92,7 +92,7 @@ public:
      */
     ATCmdParser(FileHandle *fh, const char *output_delimiter = "\r",
                 int buffer_size = 256, int timeout = 8000, bool debug = false)
-        : _fh(fh), _buffer_size(buffer_size), _oob_cb_count(0), _in_prev(0), _oobs(NULL)
+        : _fh(fh), _buffer_size(buffer_size), _oob_cb_count(0), _in_prev(0), _aborted(false), _oobs(NULL)
     {
         _buffer = new char[buffer_size];
         set_timeout(timeout);
diff --git a/platform/source/ATCmdParser.cpp b/platform/source/ATCmdParser.cpp
index 7a54f55fba..6f01a3ea79 100644
--- a/platform/source/ATCmdParser.cpp
+++ b/platform/source/ATCmdParser.cpp
@@ -397,7 +397,7 @@ void ATCmdParser::abort()
 bool ATCmdParser::process_oob()
 {
     int pre_count = _oob_cb_count;
-    recv(NULL);
+    static_cast<void>(recv(NULL));
     return _oob_cb_count != pre_count;
 }
 
diff --git a/platform/source/SysTimer.cpp b/platform/source/SysTimer.cpp
index 8186c114f8..452ccfe327 100644
--- a/platform/source/SysTimer.cpp
+++ b/platform/source/SysTimer.cpp
@@ -57,6 +57,7 @@ SysTimer<US_IN_TICK, IRQ>::SysTimer() :
     _unacknowledged_ticks(0),
     _wake_time_set(false),
     _wake_time_passed(false),
+    _wake_early(false),
     _ticking(false),
     _deep_sleep_locked(false)
 {
@@ -70,6 +71,7 @@ SysTimer<US_IN_TICK, IRQ>::SysTimer(const ticker_data_t *data) :
     _unacknowledged_ticks(0),
     _wake_time_set(false),
     _wake_time_passed(false),
+    _wake_early(false),
     _ticking(false),
     _deep_sleep_locked(false)
 {
diff --git a/platform/source/mbed_retarget.cpp b/platform/source/mbed_retarget.cpp
index b55902a4e2..6679d87219 100644
--- a/platform/source/mbed_retarget.cpp
+++ b/platform/source/mbed_retarget.cpp
@@ -826,6 +826,7 @@ int _lseek(FILEHANDLE fh, int offset, int whence)
     off_t off = lseek(fh, offset, whence);
     // Assuming INT_MAX = LONG_MAX, so we don't care about prototype difference
     if (off > INT_MAX) {
+        // Be cautious in case off_t is 64-bit
         errno = EOVERFLOW;
         return -1;
     }