diff --git a/libraries/Preferences/src/Preferences.cpp b/libraries/Preferences/src/Preferences.cpp
index 3e689c95..7ad494fe 100644
--- a/libraries/Preferences/src/Preferences.cpp
+++ b/libraries/Preferences/src/Preferences.cpp
@@ -178,8 +178,8 @@ size_t Preferences::putBytes(const char* key, const void* value, size_t len) {
     string res = "";
     if ( key != nullptr && strlen(key) > 0 && value != nullptr && len > 0) {
         modem.write_nowait(string(PROMPT(_PREF_PUT)), res, "%s%s,%d,%d\r\n", CMD_WRITE(_PREF_PUT), key, PT_BLOB, len);
-        if(modem.passthrough((uint8_t *)value, len)) {
-            return len;
+        if(modem.passthrough((uint8_t *)value, len, &res)) {
+            return atoi(res.c_str());
         }
     }
     return 0;
diff --git a/libraries/WiFiS3/src/Modem.cpp b/libraries/WiFiS3/src/Modem.cpp
index 7aa34391..b3e4038b 100644
--- a/libraries/WiFiS3/src/Modem.cpp
+++ b/libraries/WiFiS3/src/Modem.cpp
@@ -48,13 +48,17 @@ void ModemClass::end(){
 }
 
 /* -------------------------------------------------------------------------- */
-bool ModemClass::passthrough(const uint8_t *data, size_t size) {
+bool ModemClass::passthrough(const uint8_t *data, size_t size, std::string *response) {
 /* -------------------------------------------------------------------------- */
    _serial->write(data,size);
 
    std::string prompt = DO_NOT_CHECK_CMD, data_res;
    auto res = buf_read(prompt, data_res);
 
+   if(response != nullptr) {
+      *response = data_res;
+   }
+
    if(_serial_debug && _debug_level >= 2) {
       _serial_debug->print("   ANSWER (passthrough): ");
       _serial_debug->println(data_res.c_str());
diff --git a/libraries/WiFiS3/src/Modem.h b/libraries/WiFiS3/src/Modem.h
index 3f785bc9..f417cfb5 100644
--- a/libraries/WiFiS3/src/Modem.h
+++ b/libraries/WiFiS3/src/Modem.h
@@ -27,7 +27,7 @@ class ModemClass {
   bool write(const std::string &cmd, std::string &str, const char * fmt, ...);
   void write_nowait(const std::string &cmd, std::string &str, const char * fmt, ...);
 
-  bool passthrough(const uint8_t *data, size_t size);
+  bool passthrough(const uint8_t *data, size_t size, std::string *response=nullptr);
   void avoid_trim_results() {
     /* one shot - it works only 1 time the it is necessary to call again this
        funtion */