diff --git a/code/espurna/button.ino b/code/espurna/button.ino
index 24f78af7..5bd75918 100644
--- a/code/espurna/button.ino
+++ b/code/espurna/button.ino
@@ -66,7 +66,7 @@ uint8_t mapEvent(uint8_t event, uint8_t count, uint16_t length) {
 
 void buttonEvent(unsigned int id, unsigned char event) {
 
-    DEBUG_MSG("[BUTTON] Pressed #%d, event: %d\n", id, event);
+    DEBUG_MSG_P(PSTR("[BUTTON] Pressed #%d, event: %d\n"), id, event);
     if (event == 0) return;
 
     #ifdef MQTT_TOPIC_BUTTON
@@ -84,7 +84,7 @@ void buttonEvent(unsigned int id, unsigned char event) {
     if (action == BUTTON_MODE_RESET) ESP.restart();
     if (action == BUTTON_MODE_PULSE) relayPulseToggle();
     if (action == BUTTON_MODE_FACTORY) {
-        DEBUG_MSG("\n\nFACTORY RESET\n\n");
+        DEBUG_MSG_P(PSTR("\n\nFACTORY RESET\n\n"));
         settingsFactoryReset();
         ESP.restart();
     }
@@ -129,7 +129,7 @@ void buttonSetup() {
 
     #endif
 
-    DEBUG_MSG("[BUTTON] Number of buttons: %d\n", _buttons.size());
+    DEBUG_MSG_P(PSTR("[BUTTON] Number of buttons: %d\n"), _buttons.size());
 
 }
 
diff --git a/code/espurna/dht.ino b/code/espurna/dht.ino
index 11f05a18..91be1402 100644
--- a/code/espurna/dht.ino
+++ b/code/espurna/dht.ino
@@ -54,7 +54,7 @@ void dhtLoop() {
         // Check if readings are valid
         if (isnan(h) || isnan(t)) {
 
-            DEBUG_MSG("[DHT] Error reading sensor\n");
+            DEBUG_MSG_P(PSTR("[DHT] Error reading sensor\n"));
 
         } else {
 
@@ -66,8 +66,8 @@ void dhtLoop() {
             dtostrf(t, 4, 1, temperature);
             itoa((unsigned int) h, humidity, 10);
 
-            DEBUG_MSG("[DHT] Temperature: %s%s\n", temperature, (tmpUnits == TMP_CELSIUS) ? "ºC" : "ºF");
-            DEBUG_MSG("[DHT] Humidity: %s\n", humidity);
+            DEBUG_MSG_P(PSTR("[DHT] Temperature: %s%s\n"), temperature, (tmpUnits == TMP_CELSIUS) ? "ºC" : "ºF");
+            DEBUG_MSG_P(PSTR("[DHT] Humidity: %s\n"), humidity);
 
             // Send MQTT messages
             mqttSend(getSetting("dhtTmpTopic", DHT_TEMPERATURE_TOPIC).c_str(), temperature);
diff --git a/code/espurna/ds18b20.ino b/code/espurna/ds18b20.ino
index bf177627..648a422b 100644
--- a/code/espurna/ds18b20.ino
+++ b/code/espurna/ds18b20.ino
@@ -73,7 +73,7 @@ void dsLoop() {
         // Check if readings are valid
         if (isnan(t)) {
 
-            DEBUG_MSG("[DS18B20] Error reading sensor\n");
+            DEBUG_MSG_P(PSTR("[DS18B20] Error reading sensor\n"));
 
         } else {
 
@@ -87,7 +87,7 @@ void dsLoop() {
 
             dtostrf(t, 5, 1, _dsTemperatureStr);
 
-            DEBUG_MSG("[DS18B20] Temperature: %s%s\n",
+            DEBUG_MSG_P(PSTR("[DS18B20] Temperature: %s%s\n"),
                 getDSTemperatureStr(),
 			    (_dsIsConnected ? ((tmpUnits == TMP_CELSIUS) ? "ºC" : "ºF") : ""));
 
diff --git a/code/espurna/emon.ino b/code/espurna/emon.ino
index d70bd32d..ea0cbab2 100644
--- a/code/espurna/emon.ino
+++ b/code/espurna/emon.ino
@@ -142,8 +142,8 @@ void powerMonitorLoop() {
 
         char current[6];
         dtostrf(_current, 5, 2, current);
-        DEBUG_MSG("[ENERGY] Current: %sA\n", current);
-        DEBUG_MSG("[ENERGY] Power: %dW\n", int(_current * mainsVoltage));
+        DEBUG_MSG_P(PSTR("[ENERGY] Current: %sA\n"), current);
+        DEBUG_MSG_P(PSTR("[ENERGY] Power: %dW\n"), int(_current * mainsVoltage));
 
         // Update websocket clients
         char text[64];
diff --git a/code/espurna/espurna.ino b/code/espurna/espurna.ino
index a2db36b9..5dd8b02b 100644
--- a/code/espurna/espurna.ino
+++ b/code/espurna/espurna.ino
@@ -40,13 +40,14 @@ void heartbeat() {
     if (millis() < last_uptime) ++uptime_overflows;
     last_uptime = millis();
     unsigned long uptime_seconds = uptime_overflows * (UPTIME_OVERFLOW / 1000) + (last_uptime / 1000);
+    unsigned int free_heap = ESP.getFreeHeap();
 
-    DEBUG_MSG("[MAIN] Time: %s\n", (char *) NTP.getTimeDateString().c_str());
+    DEBUG_MSG_P(PSTR("[MAIN] Time: %s\n"), (char *) NTP.getTimeDateString().c_str());
     if (!mqttConnected()) {
-        DEBUG_MSG("[MAIN] Uptime: %ld seconds\n", uptime_seconds);
-        DEBUG_MSG("[MAIN] Free heap: %d bytes\n", ESP.getFreeHeap());
+        DEBUG_MSG_P(PSTR("[MAIN] Uptime: %ld seconds\n"), uptime_seconds);
+        DEBUG_MSG_P(PSTR("[MAIN] Free heap: %d bytes\n"), free_heap);
         #if ENABLE_ADC_VCC
-            DEBUG_MSG("[MAIN] Power: %d mV\n", ESP.getVcc());
+            DEBUG_MSG_P(PSTR("[MAIN] Power: %d mV\n"), ESP.getVcc());
         #endif
     }
 
@@ -72,7 +73,7 @@ void heartbeat() {
         mqttSend(MQTT_TOPIC_UPTIME, String(uptime_seconds).c_str());
     #endif
     #if (MQTT_REPORT_FREEHEAP)
-        mqttSend(MQTT_TOPIC_FREEHEAP, String(ESP.getFreeHeap()).c_str());
+        mqttSend(MQTT_TOPIC_FREEHEAP, String(free_heap).c_str());
     #endif
     #if (MQTT_REPORT_RELAY)
         relayMQTT();
@@ -113,29 +114,29 @@ void hardwareLoop() {
 
 void welcome() {
 
-    DEBUG_MSG("%s %s\n", (char *) APP_NAME, (char *) APP_VERSION);
-    DEBUG_MSG("%s\n%s\n\n", (char *) APP_AUTHOR, (char *) APP_WEBSITE);
-    DEBUG_MSG("ChipID: %06X\n", ESP.getChipId());
-    DEBUG_MSG("CPU frequency: %d MHz\n", ESP.getCpuFreqMHz());
-    DEBUG_MSG("Last reset reason: %s\n", (char *) ESP.getResetReason().c_str());
-    DEBUG_MSG("Memory size: %d bytes\n", ESP.getFlashChipSize());
-    DEBUG_MSG("Free heap: %d bytes\n", ESP.getFreeHeap());
-    DEBUG_MSG("Firmware size: %d bytes\n", ESP.getSketchSize());
-    DEBUG_MSG("Free firmware space: %d bytes\n", ESP.getFreeSketchSpace());
+    DEBUG_MSG_P(PSTR("%s %s\n"), (char *) APP_NAME, (char *) APP_VERSION);
+    DEBUG_MSG_P(PSTR("%s\n%s\n\n"), (char *) APP_AUTHOR, (char *) APP_WEBSITE);
+    DEBUG_MSG_P(PSTR("ChipID: %06X\n"), ESP.getChipId());
+    DEBUG_MSG_P(PSTR("CPU frequency: %d MHz\n"), ESP.getCpuFreqMHz());
+    DEBUG_MSG_P(PSTR("Last reset reason: %s\n"), (char *) ESP.getResetReason().c_str());
+    DEBUG_MSG_P(PSTR("Memory size: %d bytes\n"), ESP.getFlashChipSize());
+    DEBUG_MSG_P(PSTR("Free heap: %d bytes\n"), ESP.getFreeHeap());
+    DEBUG_MSG_P(PSTR("Firmware size: %d bytes\n"), ESP.getSketchSize());
+    DEBUG_MSG_P(PSTR("Free firmware space: %d bytes\n"), ESP.getFreeSketchSpace());
 
     #if not EMBEDDED_WEB
         FSInfo fs_info;
         if (SPIFFS.info(fs_info)) {
-            DEBUG_MSG("File system total size: %d bytes\n", fs_info.totalBytes);
-            DEBUG_MSG("            used size : %d bytes\n", fs_info.usedBytes);
-            DEBUG_MSG("            block size: %d bytes\n", fs_info.blockSize);
-            DEBUG_MSG("            page size : %d bytes\n", fs_info.pageSize);
-            DEBUG_MSG("            max files : %d\n", fs_info.maxOpenFiles);
-            DEBUG_MSG("            max length: %d\n", fs_info.maxPathLength);
+            DEBUG_MSG_P(PSTR("File system total size: %d bytes\n"), fs_info.totalBytes);
+            DEBUG_MSG_P(PSTR("            used size : %d bytes\n"), fs_info.usedBytes);
+            DEBUG_MSG_P(PSTR("            block size: %d bytes\n"), fs_info.blockSize);
+            DEBUG_MSG_P(PSTR("            page size : %d bytes\n"), fs_info.pageSize);
+            DEBUG_MSG_P(PSTR("            max files : %d\n"), fs_info.maxOpenFiles);
+            DEBUG_MSG_P(PSTR("            max length: %d\n"), fs_info.maxPathLength);
         }
     #endif
 
-    DEBUG_MSG("\n\n");
+    DEBUG_MSG_P(PSTR("\n\n"));
 
 }
 
diff --git a/code/espurna/fauxmo.ino b/code/espurna/fauxmo.ino
index 4450394f..03375054 100644
--- a/code/espurna/fauxmo.ino
+++ b/code/espurna/fauxmo.ino
@@ -32,7 +32,7 @@ void fauxmoSetup() {
         }
     }
     fauxmo.onMessage([relays](unsigned char device_id, const char * name, bool state) {
-        DEBUG_MSG("[FAUXMO] %s state: %s\n", name, state ? "ON" : "OFF");
+        DEBUG_MSG_P(PSTR("[FAUXMO] %s state: %s\n"), name, state ? "ON" : "OFF");
         relayStatus(device_id, state);
     });
 }
diff --git a/code/espurna/i2c.ino b/code/espurna/i2c.ino
index 221c22df..f40c0ebe 100644
--- a/code/espurna/i2c.ino
+++ b/code/espurna/i2c.ino
@@ -24,14 +24,14 @@ void i2cScan() {
         response = brzo_i2c_end_transaction();
 
         if (response == 0) {
-            DEBUG_MSG("[I2C] Device found at address 0x%02X\n", address);
+            DEBUG_MSG_P(PSTR("[I2C] Device found at address 0x%02X\n"), address);
             nDevices++;
         } else if (response != 32) {
-            //DEBUG_MSG("[I2C] Unknown error at address 0x%02X\n", address);
+            //DEBUG_MSG_P(PSTR("[I2C] Unknown error at address 0x%02X\n"), address);
         }
     }
 
-    if (nDevices == 0) DEBUG_MSG("[I2C] No devices found");
+    if (nDevices == 0) DEBUG_MSG_P(PSTR("[I2C] No devices found"));
 
 }
 
diff --git a/code/espurna/led.ino b/code/espurna/led.ino
index a81334c3..cb922779 100644
--- a/code/espurna/led.ino
+++ b/code/espurna/led.ino
@@ -77,7 +77,7 @@ void ledMQTTCallback(unsigned int type, const char * topic, const char * payload
         // Get led ID
         unsigned int ledID = t.substring(strlen(MQTT_TOPIC_LED)+1).toInt();
         if (ledID >= ledCount()) {
-            DEBUG_MSG("[LED] Wrong ledID (%d)\n", ledID);
+            DEBUG_MSG_P(PSTR("[LED] Wrong ledID (%d)\n"), ledID);
             return;
         }
 
@@ -132,8 +132,8 @@ void ledSetup() {
 
     mqttRegister(ledMQTTCallback);
 
-    DEBUG_MSG("[LED] Number of leds: %d\n", _leds.size());
-    DEBUG_MSG("[LED] Led auto indicator is %s\n", ledAuto ? "ON" : "OFF" );
+    DEBUG_MSG_P(PSTR("[LED] Number of leds: %d\n"), _leds.size());
+    DEBUG_MSG_P(PSTR("[LED] Led auto indicator is %s\n"), ledAuto ? "ON" : "OFF" );
 
 }
 
diff --git a/code/espurna/mqtt.ino b/code/espurna/mqtt.ino
index 7e8efb2e..a97bdb53 100644
--- a/code/espurna/mqtt.ino
+++ b/code/espurna/mqtt.ino
@@ -21,8 +21,8 @@ bool _mqttConnected = false;
 
 String mqttTopic;
 bool _mqttForward;
-char * _mqtt_pass = 0;
-char * _mqtt_user = 0;
+char *_mqttUser = 0;
+char *_mqttPass = 0;
 std::vector<void (*)(unsigned int, const char *, const char *)> _mqtt_callbacks;
 #if MQTT_SKIP_RETAINED
     unsigned long mqttConnectedAt = 0;
@@ -67,7 +67,7 @@ String mqttSubtopic(char * topic) {
 
 void mqttSendRaw(const char * topic, const char * message) {
     if (mqtt.connected()) {
-        DEBUG_MSG("[MQTT] Sending %s => %s\n", topic, message);
+        DEBUG_MSG_P(PSTR("[MQTT] Sending %s => %s\n"), topic, message);
         #if MQTT_USE_ASYNC
             mqtt.publish(topic, MQTT_QOS, MQTT_RETAIN, message);
         #else
@@ -90,7 +90,7 @@ void mqttSend(const char * topic, unsigned int index, const char * message) {
 
 void mqttSubscribeRaw(const char * topic) {
     if (mqtt.connected() && (strlen(topic) > 0)) {
-        DEBUG_MSG("[MQTT] Subscribing to %s\n", topic);
+        DEBUG_MSG_P(PSTR("[MQTT] Subscribing to %s\n"), topic);
         mqtt.subscribe(topic, MQTT_QOS);
     }
 }
@@ -111,7 +111,7 @@ void mqttRegister(void (*callback)(unsigned int, const char *, const char *)) {
 
 void _mqttOnConnect() {
 
-    DEBUG_MSG("[MQTT] Connected!\n");
+    DEBUG_MSG_P(PSTR("[MQTT] Connected!\n"));
 
     #if MQTT_SKIP_RETAINED
         mqttConnectedAt = millis();
@@ -135,7 +135,7 @@ void _mqttOnConnect() {
 
 void _mqttOnDisconnect() {
 
-    DEBUG_MSG("[MQTT] Disconnected!\n");
+    DEBUG_MSG_P(PSTR("[MQTT] Disconnected!\n"));
 
     // Send disconnect event to subscribers
     for (unsigned char i = 0; i < _mqtt_callbacks.size(); i++) {
@@ -149,14 +149,14 @@ void _mqttOnMessage(char* topic, char* payload, unsigned int len) {
     char message[len + 1];
     strlcpy(message, (char *) payload, len + 1);
 
-    DEBUG_MSG("[MQTT] Received %s => %s", topic, message);
+    DEBUG_MSG_P(PSTR("[MQTT] Received %s => %s"), topic, message);
     #if MQTT_SKIP_RETAINED
         if (millis() - mqttConnectedAt < MQTT_SKIP_TIME) {
-			DEBUG_MSG(" - SKIPPED\n");
+			DEBUG_MSG_P(PSTR(" - SKIPPED\n"));
 			return;
 		}
     #endif
-	DEBUG_MSG("\n");
+	DEBUG_MSG_P(PSTR("\n"));
 
     // Check system topics
     String t = mqttSubtopic((char *) topic);
@@ -185,7 +185,7 @@ void mqttConnect() {
             static unsigned long last_try = millis();
             if (millis() - last_try < MQTT_TRY_INTERVAL) {
                 if (++tries > MQTT_MAX_TRIES) {
-                    DEBUG_MSG("[MQTT] MQTT_MAX_TRIES met, disconnecting from WiFi\n");
+                    DEBUG_MSG_P(PSTR("[MQTT] MQTT_MAX_TRIES met, disconnecting from WiFi\n"));
                     wifiDisconnect();
                     tries = 0;
                     return;
@@ -198,34 +198,37 @@ void mqttConnect() {
 
         mqtt.disconnect();
 
+        if (_mqttUser) free(_mqttUser);
+        if (_mqttPass) free(_mqttPass);
+
         char * host = strdup(getSetting("mqttServer", MQTT_SERVER).c_str());
         unsigned int port = getSetting("mqttPort", MQTT_PORT).toInt();
-        char * user = strdup(getSetting("mqttUser").c_str());
-        char * pass = strdup(getSetting("mqttPassword").c_str());
+        _mqttUser = strdup(getSetting("mqttUser").c_str());
+        _mqttPass = strdup(getSetting("mqttPassword").c_str());
 
-        DEBUG_MSG("[MQTT] Connecting to broker at %s:%d", host, port);
+        DEBUG_MSG_P(PSTR("[MQTT] Connecting to broker at %s:%d"), host, port);
         mqtt.setServer(host, port);
 
         #if MQTT_USE_ASYNC
 
             mqtt.setKeepAlive(MQTT_KEEPALIVE).setCleanSession(false);
     	    mqtt.setWill((mqttTopic + MQTT_TOPIC_STATUS).c_str(), MQTT_QOS, MQTT_RETAIN, "0");
-            if ((strlen(user) > 0) && (strlen(pass) > 0)) {
-                DEBUG_MSG(" as user '%s'.", user);
-                mqtt.setCredentials(user, pass);
+            if ((strlen(_mqttUser) > 0) && (strlen(_mqttPass) > 0)) {
+                DEBUG_MSG_P(PSTR(" as user '%s'."), _mqttUser);
+                mqtt.setCredentials(_mqttUser, _mqttPass);
             }
-            DEBUG_MSG("\n");
+            DEBUG_MSG_P(PSTR("\n"));
             mqtt.connect();
 
         #else
 
             bool response;
 
-            if ((strlen(user) > 0) && (strlen(pass) > 0)) {
-                DEBUG_MSG(" as user '%s'\n", user);
-                response = mqtt.connect(getIdentifier().c_str(), user, pass, (mqttTopic + MQTT_TOPIC_STATUS).c_str(), MQTT_QOS, MQTT_RETAIN, "0");
+            if ((strlen(_mqttUser) > 0) && (strlen(_mqttPass) > 0)) {
+                DEBUG_MSG_P(PSTR(" as user '%s'\n"), _mqttUser);
+                response = mqtt.connect(getIdentifier().c_str(), _mqttUser, _mqttPass, (mqttTopic + MQTT_TOPIC_STATUS).c_str(), MQTT_QOS, MQTT_RETAIN, "0");
             } else {
-                DEBUG_MSG("\n");
+                DEBUG_MSG_P(PSTR("\n"));
                 response = mqtt.connect(getIdentifier().c_str(), (mqttTopic + MQTT_TOPIC_STATUS).c_str(), MQTT_QOS, MQTT_RETAIN, "0");
             }
 
@@ -233,14 +236,12 @@ void mqttConnect() {
                 _mqttOnConnect();
                 _mqttConnected = true;
             } else {
-                DEBUG_MSG("[MQTT] Connection failed\n");
+                DEBUG_MSG_P(PSTR("[MQTT] Connection failed\n"));
             }
 
         #endif
 
         free(host);
-        free(user);
-        free(pass);
 
         String mqttSetter = getSetting("mqttSetter", MQTT_USE_SETTER);
         String mqttGetter = getSetting("mqttGetter", MQTT_USE_GETTER);
diff --git a/code/espurna/nofuss.ino b/code/espurna/nofuss.ino
index 97e4dd1f..c6b5d0fc 100644
--- a/code/espurna/nofuss.ino
+++ b/code/espurna/nofuss.ino
@@ -23,46 +23,46 @@ NoFUSSClient.setVersion(APP_VERSION);
 NoFUSSClient.onMessage([](nofuss_t code) {
 
     if (code == NOFUSS_START) {
-    	DEBUG_MSG("[NoFUSS] Start\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Start\n"));
     }
 
     if (code == NOFUSS_UPTODATE) {
-    	DEBUG_MSG("[NoFUSS] Already in the last version\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Already in the last version\n"));
     }
 
     if (code == NOFUSS_PARSE_ERROR) {
-    	DEBUG_MSG("[NoFUSS] Error parsing server response\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Error parsing server response\n"));
     }
 
     if (code == NOFUSS_UPDATING) {
-    	DEBUG_MSG("[NoFUSS] Updating");
-	    DEBUG_MSG("         New version: %s\n", (char *) NoFUSSClient.getNewVersion().c_str());
-    	DEBUG_MSG("         Firmware: %s\n", (char *) NoFUSSClient.getNewFirmware().c_str());
-    	DEBUG_MSG("         File System: %s", (char *) NoFUSSClient.getNewFileSystem().c_str());
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Updating");
+	    DEBUG_MSG_P(PSTR("         New version: %s\n"), (char *) NoFUSSClient.getNewVersion().c_str());
+    	DEBUG_MSG_P(PSTR("         Firmware: %s\n"), (char *) NoFUSSClient.getNewFirmware().c_str());
+    	DEBUG_MSG_P(PSTR("         File System: %s"), (char *) NoFUSSClient.getNewFileSystem().c_str());
     }
 
     if (code == NOFUSS_FILESYSTEM_UPDATE_ERROR) {
-    	DEBUG_MSG("[NoFUSS] File System Update Error: %s\n", (char *) NoFUSSClient.getErrorString().c_str());
+    	DEBUG_MSG_P(PSTR("[NoFUSS] File System Update Error: %s\n"), (char *) NoFUSSClient.getErrorString().c_str());
     }
 
     if (code == NOFUSS_FILESYSTEM_UPDATED) {
-    	DEBUG_MSG("[NoFUSS] File System Updated\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] File System Updated\n"));
     }
 
     if (code == NOFUSS_FIRMWARE_UPDATE_ERROR) {
-        DEBUG_MSG("[NoFUSS] Firmware Update Error: %s\n", (char *) NoFUSSClient.getErrorString().c_str());
+        DEBUG_MSG_P(PSTR("[NoFUSS] Firmware Update Error: %s\n"), (char *) NoFUSSClient.getErrorString().c_str());
     }
 
     if (code == NOFUSS_FIRMWARE_UPDATED) {
-    	DEBUG_MSG("[NoFUSS] Firmware Updated\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Firmware Updated\n"));
     }
 
     if (code == NOFUSS_RESET) {
-    	DEBUG_MSG("[NoFUSS] Resetting board\n");
+    	DEBUG_MSG_P(PSTR("[NoFUSS] Resetting board\n"));
     }
 
     if (code == NOFUSS_END) {
-	    DEBUG_MSG("[NoFUSS] End\n");
+	    DEBUG_MSG_P(PSTR("[NoFUSS] End\n"));
     }
 
 });
diff --git a/code/espurna/ntp.ino b/code/espurna/ntp.ino
index 99cbdbaa..07cd9676 100644
--- a/code/espurna/ntp.ino
+++ b/code/espurna/ntp.ino
@@ -24,12 +24,12 @@ void ntpSetup() {
     NTP.onNTPSyncEvent([](NTPSyncEvent_t error) {
         if (error) {
             if (error == noResponse) {
-                DEBUG_MSG("[NTP] Error: NTP server not reachable\n");
+                DEBUG_MSG_P(PSTR("[NTP] Error: NTP server not reachable\n"));
             } else if (error == invalidAddress) {
-                DEBUG_MSG("[NTP] Error: Invalid NTP server address\n");
+                DEBUG_MSG_P(PSTR("[NTP] Error: Invalid NTP server address\n"));
             }
         } else {
-            DEBUG_MSG("[NTP] Time: %s\n", (char *) NTP.getTimeDateString(NTP.getLastNTPSync()).c_str());
+            DEBUG_MSG_P(PSTR("[NTP] Time: %s\n"), (char *) NTP.getTimeDateString(NTP.getLastNTPSync()).c_str());
         }
     });
 
diff --git a/code/espurna/ota.ino b/code/espurna/ota.ino
index 07f27c5d..584f2ac0 100644
--- a/code/espurna/ota.ino
+++ b/code/espurna/ota.ino
@@ -23,28 +23,28 @@ void otaSetup() {
     otaConfigure();
 
     ArduinoOTA.onStart([]() {
-        DEBUG_MSG("[OTA] Start\n");
+        DEBUG_MSG_P(PSTR("[OTA] Start\n"));
         wsSend("{\"message\": \"OTA update started\"}");
     });
 
     ArduinoOTA.onEnd([]() {
-        DEBUG_MSG("\n[OTA] End\n");
+        DEBUG_MSG_P(PSTR("\n[OTA] End\n"));
         wsSend("{\"action\": \"reload\"}");
         delay(100);
     });
 
     ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {
-        DEBUG_MSG("[OTA] Progress: %u%%\r", (progress / (total / 100)));
+        DEBUG_MSG_P(PSTR("[OTA] Progress: %u%%\r"), (progress / (total / 100)));
     });
 
     ArduinoOTA.onError([](ota_error_t error) {
         #if DEBUG_PORT
-            DEBUG_MSG("\n[OTA] Error[%u]: ", error);
-            if (error == OTA_AUTH_ERROR) DEBUG_MSG("Auth Failed\n");
-            else if (error == OTA_BEGIN_ERROR) DEBUG_MSG("Begin Failed\n");
-            else if (error == OTA_CONNECT_ERROR) DEBUG_MSG("Connect Failed\n");
-            else if (error == OTA_RECEIVE_ERROR) DEBUG_MSG("Receive Failed\n");
-            else if (error == OTA_END_ERROR) DEBUG_MSG("End Failed\n");
+            DEBUG_MSG_P(PSTR("\n[OTA] Error[%u]: "), error);
+            if (error == OTA_AUTH_ERROR) DEBUG_MSG_P(PSTR("Auth Failed\n"));
+            else if (error == OTA_BEGIN_ERROR) DEBUG_MSG_P(PSTR("Begin Failed\n"));
+            else if (error == OTA_CONNECT_ERROR) DEBUG_MSG_P(PSTR("Connect Failed\n"));
+            else if (error == OTA_RECEIVE_ERROR) DEBUG_MSG_P(PSTR("Receive Failed\n"));
+            else if (error == OTA_END_ERROR) DEBUG_MSG_P(PSTR("End Failed\n"));
         #endif
     });
 
diff --git a/code/espurna/pow.ino b/code/espurna/pow.ino
index b6293320..8c0be781 100644
--- a/code/espurna/pow.ino
+++ b/code/espurna/pow.ino
@@ -38,13 +38,13 @@ void powEnable(bool status) {
             attachInterrupt(POW_CF1_PIN, hlw8012_cf1_interrupt, CHANGE);
             attachInterrupt(POW_CF_PIN, hlw8012_cf_interrupt, CHANGE);
         #endif
-        DEBUG_MSG("[POW] Enabled\n");
+        DEBUG_MSG_P(PSTR("[POW] Enabled\n"));
     } else {
         #if POW_USE_INTERRUPTS == 1
             detachInterrupt(POW_CF1_PIN);
             detachInterrupt(POW_CF_PIN);
         #endif
-        DEBUG_MSG("[POW] Disabled\n");
+        DEBUG_MSG_P(PSTR("[POW] Disabled\n"));
     }
 }
 
diff --git a/code/espurna/relay.ino b/code/espurna/relay.ino
index e012e446..6c3f5ec3 100644
--- a/code/espurna/relay.ino
+++ b/code/espurna/relay.ino
@@ -153,7 +153,7 @@ bool relayStatus(unsigned char id, bool status, bool report) {
 
     if (relayStatus(id) != status) {
 
-        DEBUG_MSG("[RELAY] %d => %s\n", id, status ? "ON" : "OFF");
+        DEBUG_MSG_P(PSTR("[RELAY] %d => %s\n"), id, status ? "ON" : "OFF");
         changed = true;
 
         relayProviderStatus(id, status);
@@ -345,7 +345,7 @@ void relayDomoticzSetup() {
                 DynamicJsonBuffer jsonBuffer;
                 JsonObject& root = jsonBuffer.parseObject((char *) payload);
                 if (!root.success()) {
-                    DEBUG_MSG("[DOMOTICZ] Error parsing data\n");
+                    DEBUG_MSG_P(PSTR("[DOMOTICZ] Error parsing data\n"));
                     return;
                 }
 
@@ -354,7 +354,7 @@ void relayDomoticzSetup() {
                 int relayID = relayFromIdx(idx);
                 if (relayID >= 0) {
                     unsigned long value = root["nvalue"];
-                    DEBUG_MSG("[DOMOTICZ] Received value %d for IDX %d\n", value, idx);
+                    DEBUG_MSG_P(PSTR("[DOMOTICZ] Received value %d for IDX %d\n"), value, idx);
                     relayStatus(relayID, value == 1);
                 }
 
@@ -414,7 +414,7 @@ void relayMQTTCallback(unsigned int type, const char * topic, const char * paylo
         // Get relay ID
         unsigned int relayID = t.substring(strlen(MQTT_TOPIC_RELAY)+1).toInt();
         if (relayID >= relayCount()) {
-            DEBUG_MSG("[RELAY] Wrong relayID (%d)\n", relayID);
+            DEBUG_MSG_P(PSTR("[RELAY] Wrong relayID (%d)\n"), relayID);
             return;
         }
 
@@ -482,6 +482,6 @@ void relaySetup() {
         relayDomoticzSetup();
     #endif
 
-    DEBUG_MSG("[RELAY] Number of relays: %d\n", _relays.size());
+    DEBUG_MSG_P(PSTR("[RELAY] Number of relays: %d\n"), _relays.size());
 
 }
diff --git a/code/espurna/rf.ino b/code/espurna/rf.ino
index 0933ed83..70b0895a 100644
--- a/code/espurna/rf.ino
+++ b/code/espurna/rf.ino
@@ -21,7 +21,7 @@ unsigned long rfCodeOFF = 0;
 void rfLoop() {
     return;
     if (rfCode == 0) return;
-    DEBUG_MSG("[RF] Received code: %lu\n", rfCode);
+    DEBUG_MSG_P(PSTR("[RF] Received code: %lu\n"), rfCode);
     if (rfCode == rfCodeON) relayStatus(0, true);
     if (rfCode == rfCodeOFF) relayStatus(0, false);
     rfCode = 0;
@@ -51,8 +51,8 @@ void rfBuildCodes() {
     rfCodeOFF = code + 2;
     rfCodeON = code + 6;
 
-    DEBUG_MSG("[RF] Code ON : %lu\n", rfCodeON);
-    DEBUG_MSG("[RF] Code OFF: %lu\n", rfCodeOFF);
+    DEBUG_MSG_P(PSTR("[RF] Code ON : %lu\n"), rfCodeON);
+    DEBUG_MSG_P(PSTR("[RF] Code OFF: %lu\n"), rfCodeOFF);
 
 }
 
@@ -66,26 +66,26 @@ void rfSetup() {
     rfBuildCodes();
     RemoteReceiver::init(RF_PIN, 3, rfCallback);
     RemoteReceiver::disable();
-    DEBUG_MSG("[RF] Disabled\n");
+    DEBUG_MSG_P(PSTR("[RF] Disabled\n"));
 
     static WiFiEventHandler e1 = WiFi.onStationModeDisconnected([](const WiFiEventStationModeDisconnected& event) {
         RemoteReceiver::disable();
-        DEBUG_MSG("[RF] Disabled\n");
+        DEBUG_MSG_P(PSTR("[RF] Disabled\n"));
     });
 
     static WiFiEventHandler e2 = WiFi.onSoftAPModeStationDisconnected([](const WiFiEventSoftAPModeStationDisconnected& event) {
         RemoteReceiver::disable();
-        DEBUG_MSG("[RF] Disabled\n");
+        DEBUG_MSG_P(PSTR("[RF] Disabled\n"));
         });
 
     static WiFiEventHandler e3 = WiFi.onStationModeConnected([](const WiFiEventStationModeConnected& event) {
         RemoteReceiver::enable();
-        DEBUG_MSG("[RF] Enabled\n");
+        DEBUG_MSG_P(PSTR("[RF] Enabled\n"));
     });
 
     static WiFiEventHandler e4 = WiFi.onSoftAPModeStationConnected([](const WiFiEventSoftAPModeStationConnected& event) {
         RemoteReceiver::enable();
-        DEBUG_MSG("[RF] Enabled\n");
+        DEBUG_MSG_P(PSTR("[RF] Enabled\n"));
     });
 
 }
diff --git a/code/espurna/settings.ino b/code/espurna/settings.ino
index 9ebb904e..f10f9666 100644
--- a/code/espurna/settings.ino
+++ b/code/espurna/settings.ino
@@ -163,8 +163,8 @@ void settingsSetup() {
         e->response(Embedis::OK);
     });
 
-    DEBUG_MSG("[SETTINGS] EEPROM size: %d bytes\n", SPI_FLASH_SEC_SIZE);
-    DEBUG_MSG("[SETTINGS] Settings size: %d bytes\n", settingsSize());
+    DEBUG_MSG_P(PSTR("[SETTINGS] EEPROM size: %d bytes\n"), SPI_FLASH_SEC_SIZE);
+    DEBUG_MSG_P(PSTR("[SETTINGS] Settings size: %d bytes\n"), settingsSize());
 
 }
 
@@ -191,7 +191,7 @@ bool delSetting(const String& key) {
 }
 
 void saveSettings() {
-    DEBUG_MSG("[SETTINGS] Saving\n");
+    DEBUG_MSG_P(PSTR("[SETTINGS] Saving\n"));
     #if not AUTO_SAVE
         EEPROM.commit();
     #endif
diff --git a/code/espurna/web.ino b/code/espurna/web.ino
index 0e0a9b72..9a488a09 100644
--- a/code/espurna/web.ino
+++ b/code/espurna/web.ino
@@ -45,13 +45,13 @@ char _last_modified[50];
 
 bool wsSend(const char * payload) {
     if (ws.count() > 0) {
-        DEBUG_MSG("[WEBSOCKET] Broadcasting '%s'\n", payload);
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] Broadcasting '%s'\n"), payload);
         ws.textAll(payload);
     }
 }
 
 bool wsSend(uint32_t client_id, const char * payload) {
-    DEBUG_MSG("[WEBSOCKET] Sending '%s' to #%ld\n", payload, client_id);
+    DEBUG_MSG_P(PSTR("[WEBSOCKET] Sending '%s' to #%ld\n"), payload, client_id);
     ws.text(client_id, payload);
 }
 
@@ -73,7 +73,7 @@ void _wsParse(uint32_t client_id, uint8_t * payload, size_t length) {
     DynamicJsonBuffer jsonBuffer;
     JsonObject& root = jsonBuffer.parseObject((char *) payload);
     if (!root.success()) {
-        DEBUG_MSG("[WEBSOCKET] Error parsing data\n");
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] Error parsing data\n"));
         ws.text(client_id, "{\"message\": \"Error parsing data!\"}");
         return;
     }
@@ -83,7 +83,7 @@ void _wsParse(uint32_t client_id, uint8_t * payload, size_t length) {
 
         String action = root["action"];
 
-        DEBUG_MSG("[WEBSOCKET] Requested action: %s\n", action.c_str());
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] Requested action: %s\n"), action.c_str());
 
         if (action.equals("reset")) {
             ESP.restart();
@@ -123,7 +123,7 @@ void _wsParse(uint32_t client_id, uint8_t * payload, size_t length) {
         if (action.equals("relay") && root.containsKey("data")) {
 
             JsonObject& data = root["data"];
-            
+
             if (data.containsKey("status")) {
 
                 bool state = (strcmp(data["status"], "1") == 0);
@@ -152,7 +152,7 @@ void _wsParse(uint32_t client_id, uint8_t * payload, size_t length) {
     if (root.containsKey("config") && root["config"].is<JsonArray&>()) {
 
         JsonArray& config = root["config"];
-        DEBUG_MSG("[WEBSOCKET] Parsing configuration data\n");
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] Parsing configuration data\n"));
 
         unsigned char webMode = WEB_MODE_NORMAL;
 
@@ -274,7 +274,7 @@ void _wsParse(uint32_t client_id, uint8_t * payload, size_t length) {
             }
 
             if (value != getSetting(key)) {
-                //DEBUG_MSG("[WEBSOCKET] Storing %s = %s\n", key.c_str(), value.c_str());
+                //DEBUG_MSG_P(PSTR("[WEBSOCKET] Storing %s = %s\n", key.c_str(), value.c_str()));
                 setSetting(key, value);
                 save = changed = true;
                 if (key.startsWith("mqtt")) changedMQTT = true;
@@ -533,7 +533,7 @@ bool _wsAuth(AsyncWebSocketClient * client) {
     }
 
     if (index == WS_BUFFER_SIZE) {
-        DEBUG_MSG("[WEBSOCKET] Validation check failed\n");
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] Validation check failed\n"));
         ws.text(client->id(), "{\"message\": \"Session expired, please reload page...\"}");
         return false;
     }
@@ -553,14 +553,14 @@ void _wsEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventTy
 
     if (type == WS_EVT_CONNECT) {
         IPAddress ip = client->remoteIP();
-        DEBUG_MSG("[WEBSOCKET] #%u connected, ip: %d.%d.%d.%d, url: %s\n", client->id(), ip[0], ip[1], ip[2], ip[3], server->url());
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] #%u connected, ip: %d.%d.%d.%d, url: %s\n"), client->id(), ip[0], ip[1], ip[2], ip[3], server->url());
         _wsStart(client->id());
     } else if(type == WS_EVT_DISCONNECT) {
-        DEBUG_MSG("[WEBSOCKET] #%u disconnected\n", client->id());
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] #%u disconnected\n"), client->id());
     } else if(type == WS_EVT_ERROR) {
-        DEBUG_MSG("[WEBSOCKET] #%u error(%u): %s\n", client->id(), *((uint16_t*)arg), (char*)data);
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] #%u error(%u): %s\n"), client->id(), *((uint16_t*)arg), (char*)data);
     } else if(type == WS_EVT_PONG) {
-        DEBUG_MSG("[WEBSOCKET] #%u pong(%u): %s\n", client->id(), len, len ? (char*) data : "");
+        DEBUG_MSG_P(PSTR("[WEBSOCKET] #%u pong(%u): %s\n"), client->id(), len, len ? (char*) data : "");
     } else if(type == WS_EVT_DATA) {
 
         AwsFrameInfo * info = (AwsFrameInfo*)arg;
@@ -588,7 +588,7 @@ void _wsEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventTy
 // -----------------------------------------------------------------------------
 
 void webLogRequest(AsyncWebServerRequest *request) {
-    DEBUG_MSG("[WEBSERVER] Request: %s %s\n", request->methodToString(), request->url().c_str());
+    DEBUG_MSG_P(PSTR("[WEBSERVER] Request: %s %s\n"), request->methodToString(), request->url().c_str());
 }
 
 bool _authenticate(AsyncWebServerRequest *request) {
@@ -601,20 +601,20 @@ bool _authenticate(AsyncWebServerRequest *request) {
 bool _authAPI(AsyncWebServerRequest *request) {
 
     if (getSetting("apiEnabled").toInt() == 0) {
-        DEBUG_MSG("[WEBSERVER] HTTP API is not enabled\n");
+        DEBUG_MSG_P(PSTR("[WEBSERVER] HTTP API is not enabled\n"));
         request->send(403);
         return false;
     }
 
     if (!request->hasParam("apikey", (request->method() == HTTP_PUT))) {
-        DEBUG_MSG("[WEBSERVER] Missing apikey parameter\n");
+        DEBUG_MSG_P(PSTR("[WEBSERVER] Missing apikey parameter\n"));
         request->send(403);
         return false;
     }
 
     AsyncWebParameter* p = request->getParam("apikey", (request->method() == HTTP_PUT));
     if (!p->value().equals(getSetting("apiKey"))) {
-        DEBUG_MSG("[WEBSERVER] Wrong apikey parameter\n");
+        DEBUG_MSG_P(PSTR("[WEBSERVER] Wrong apikey parameter\n"));
         request->send(403);
         return false;
     }
@@ -725,7 +725,7 @@ void _onRPC(AsyncWebServerRequest *request) {
 
         AsyncWebParameter* p = request->getParam("action");
         String action = p->value();
-        DEBUG_MSG("[RPC] Action: %s\n", action.c_str());
+        DEBUG_MSG_P(PSTR("[RPC] Action: %s\n"), action.c_str());
 
         if (action.equals("reset")) {
             response = 200;
@@ -853,6 +853,6 @@ void webSetup() {
 
     // Run server
     _server->begin();
-    DEBUG_MSG("[WEBSERVER] Webserver running on port %d\n", getSetting("webPort", WEBSERVER_PORT).toInt());
+    DEBUG_MSG_P(PSTR("[WEBSERVER] Webserver running on port %d\n"), getSetting("webPort", WEBSERVER_PORT).toInt());
 
 }