diff --git a/libraries/WiFiS3/src/Modem.cpp b/libraries/WiFiS3/src/Modem.cpp
index c1dba332..7aa34391 100644
--- a/libraries/WiFiS3/src/Modem.cpp
+++ b/libraries/WiFiS3/src/Modem.cpp
@@ -75,6 +75,9 @@ bool ModemClass::passthrough(const uint8_t *data, size_t size) {
 /* -------------------------------------------------------------------------- */
 void ModemClass::write_nowait(const string &cmd, string &str, const char * fmt, ...) {
 /* -------------------------------------------------------------------------- */
+   (void)cmd;
+   (void)str;
+
    va_list va;
    va_start (va, fmt);
    vsnprintf((char *)tx_buff, MAX_BUFF_SIZE, fmt, va);
@@ -318,6 +321,7 @@ ModemClass::ParseResult ModemClass::buf_read(const string &prompt, string &data_
          if(c == '\n') {
             state = at_parse_state_t::Res;
          }
+         /* fall through */
 
          /*
           * break is volountary not present, to cover for cases where the response status is in the
diff --git a/libraries/WiFiS3/src/WiFi.cpp b/libraries/WiFiS3/src/WiFi.cpp
index 17d78fef..7e73b94f 100644
--- a/libraries/WiFiS3/src/WiFi.cpp
+++ b/libraries/WiFiS3/src/WiFi.cpp
@@ -25,7 +25,6 @@ const char* CWifi::firmwareVersion() {
 /* -------------------------------------------------------------------------- */
 uint32_t CWifi::firmwareVersionU32() {
 /* -------------------------------------------------------------------------- */
-   uint8_t ret[4];
    string res = "";
    modem.begin();
    if(modem.write(string(PROMPT(_FWVERSION_U32)), res, CMD_READ(_FWVERSION_U32))) {
diff --git a/libraries/WiFiS3/src/WiFiClient.cpp b/libraries/WiFiS3/src/WiFiClient.cpp
index 143f92da..9e6d0926 100644
--- a/libraries/WiFiS3/src/WiFiClient.cpp
+++ b/libraries/WiFiS3/src/WiFiClient.cpp
@@ -128,7 +128,7 @@ int WiFiClient::_read() {
 
       if(modem.write(string(PROMPT(_CLIENTRECEIVE)),res, "%s%d,%d\r\n" , CMD_WRITE(_CLIENTRECEIVE), _sock, size)) {
          if(res.size() > 0) {
-            for(int i = 0, rv = 0; i < size && i < res.size(); i++) {
+            for(uint32_t i = 0, rv = 0; i < size && i < res.size(); i++) {
                rx_buffer->store((uint8_t)res[i]);
                rv++;
             }
@@ -168,7 +168,7 @@ int WiFiClient::read(uint8_t *buf, size_t size) {
    int rv = 0;
    bool go_on = true;
    if(_sock >= 0 && rx_buffer != nullptr) {
-      for(int i = 0; i < size && go_on; i++) {
+      for(size_t i = 0; i < size && go_on; i++) {
          bool is_read = false;
          *(buf+i) = rx_buffer->read(&is_read);
          if(is_read) {
diff --git a/libraries/WiFiS3/src/WiFiClient.h b/libraries/WiFiS3/src/WiFiClient.h
index 81f5afae..63b019c3 100644
--- a/libraries/WiFiS3/src/WiFiClient.h
+++ b/libraries/WiFiS3/src/WiFiClient.h
@@ -70,14 +70,13 @@ class WiFiClient : public Client {
 
 protected:
   int _sock;
+  bool destroy_at_distructor;
   int _connectionTimeout = 0;
   void getSocket();
   static constexpr uint32_t RX_BUFFER_DIM = 1024;
   std::shared_ptr<FifoBuffer<uint8_t,RX_BUFFER_DIM>> rx_buffer;
   int _read();
   void read_if_needed(size_t s);
-  bool destroy_at_distructor;
-
 
 };
 
diff --git a/libraries/WiFiS3/src/WiFiFileSystem.cpp b/libraries/WiFiS3/src/WiFiFileSystem.cpp
index 938f2d8b..8dc7fa8b 100644
--- a/libraries/WiFiS3/src/WiFiFileSystem.cpp
+++ b/libraries/WiFiS3/src/WiFiFileSystem.cpp
@@ -20,6 +20,7 @@ size_t WiFiFileSystem::writefile(const char* name, const char* data, size_t size
    if(modem.passthrough((uint8_t *)data, size)) {
       return size;
    }
+   return 0;
 }
 
 /* -------------------------------------------------------------------------- */
diff --git a/libraries/WiFiS3/src/WiFiSSLClient.cpp b/libraries/WiFiS3/src/WiFiSSLClient.cpp
index 91b6951e..bfe7c488 100644
--- a/libraries/WiFiS3/src/WiFiSSLClient.cpp
+++ b/libraries/WiFiS3/src/WiFiSSLClient.cpp
@@ -148,7 +148,7 @@ int WiFiSSLClient::_read() {
       modem.read_using_size();
       if(modem.write(string(PROMPT(_SSLCLIENTRECEIVE)),res, "%s%d,%d\r\n" , CMD_WRITE(_SSLCLIENTRECEIVE), _sock, size)) {
          if(res.size() > 0) {
-            for(int i = 0, rv = 0; i < size && i < res.size(); i++) {
+            for(uint32_t i = 0, rv = 0; i < size && i < res.size(); i++) {
                rx_buffer->store((uint8_t)res[i]);
                rv++;
             }
@@ -185,7 +185,7 @@ int WiFiSSLClient::read(uint8_t *buf, size_t size) {
    read_if_needed(size);
    int rv = 0;
    bool go_on = true;
-   for(int i = 0; i < size && go_on; i++) {
+   for(size_t i = 0; i < size && go_on; i++) {
       bool is_read = false;
       *(buf+i) = rx_buffer->read(&is_read);
       if(is_read) {
diff --git a/libraries/WiFiS3/src/WiFiUdp.cpp b/libraries/WiFiS3/src/WiFiUdp.cpp
index 5337c836..f229485c 100644
--- a/libraries/WiFiS3/src/WiFiUdp.cpp
+++ b/libraries/WiFiS3/src/WiFiUdp.cpp
@@ -181,7 +181,7 @@ int WiFiUDP::_read() {
       modem.read_using_size();
       if(modem.write(string(PROMPT(_UDPREAD)),res, "%s%d,%d\r\n" , CMD_WRITE(_UDPREAD), _sock, size)) {
          if(res.size() > 0) {
-            for(int i = 0, rv = 0; i < size && i < res.size(); i++) {
+            for(uint32_t i = 0, rv = 0; i < size && i < res.size(); i++) {
                rx_buffer.store((uint8_t)res[i]);
                rv++;
             }
@@ -218,7 +218,7 @@ int WiFiUDP::read(unsigned char* buf, size_t size) {
    read_if_needed(size);
    int rv = 0;
    bool go_on = true;
-   for(int i = 0; i < size && go_on; i++) {
+   for(size_t i = 0; i < size && go_on; i++) {
       bool is_read = false;
       *(buf+i) = rx_buffer.read(&is_read);
       if(is_read) {