diff --git a/src/logmessages.h b/src/logmessages.h
index 8f79a3f..8e08bea 100644
--- a/src/logmessages.h
+++ b/src/logmessages.h
@@ -154,4 +154,8 @@ static const char restoredLastRfidFromNVS[] PROGMEM = "Letzte RFID wurde aus NVS
 static const char failedOpenFileForWrite[] PROGMEM = "Öffnen der Datei für den Schreibvorgang fehlgeschlagen";
 static const char fileWritten[] PROGMEM = "Schreibe Datei";
 static const char writeFailed[] PROGMEM = "Schreibvorgang fehlgeschlagen";
-static const char writingFile[] PROGMEM = "Schreibe Datei";
\ No newline at end of file
+static const char writingFile[] PROGMEM = "Schreibe Datei";
+static const char failedToOpenFileForAppending[] PROGMEM = "Öffnen der Datei zum Schreiben der JSON-Datei fehlgeschlagen";
+static const char listingDirectory[] PROGMEM = "Verzeichnisinhalt anzeigen";
+static const char failedToOpenDirectory[] PROGMEM = "Öffnen des Verzeichnisses fehlgeschlagen";
+static const char notADirectory[] PROGMEM = "Kein Verzeichnis";
\ No newline at end of file
diff --git a/src/logmessages_EN.h b/src/logmessages_EN.h
index e514f5f..497793e 100644
--- a/src/logmessages_EN.h
+++ b/src/logmessages_EN.h
@@ -154,4 +154,8 @@ static const char restoredLastRfidFromNVS[] PROGMEM = "Restored last RFID from N
 static const char failedOpenFileForWrite[] PROGMEM = "Failed to open file for writing";
 static const char fileWritten[] PROGMEM = "File written";
 static const char writeFailed[] PROGMEM = "Write failed";
-static const char writingFile[] PROGMEM = "Writing file";
\ No newline at end of file
+static const char writingFile[] PROGMEM = "Writing file";
+static const char failedToOpenFileForAppending[] PROGMEM = "Failed to open file for appending";
+static const char listingDirectory[] PROGMEM = "Listing directory";
+static const char failedToOpenDirectory[] PROGMEM = "Failed to open directory";
+static const char notADirectory[] PROGMEM = "Not a directory";
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index e0216eb..5885126 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -310,9 +310,7 @@ void buttonHandler();
 void deepSleepManager(void);
 void doButtonActions(void);
 void doRfidCardModifications(const uint32_t mod);
-#ifndef SD_NOT_MANDATORY_ENABLE
-    bool dumpNvsToSd(char *_namespace, char *_destFile);
-#endif
+bool dumpNvsToSd(char *_namespace, char *_destFile);
 bool endsWith (const char *str, const char *suf);
 bool fileValid(const char *_fileItem);
 void freeMultiCharArray(char **arr, const uint32_t cnt);
@@ -476,13 +474,13 @@ bool isFirstJSONtNode = true;
  */
 void appendNodeToJSONFile(fs::FS &fs, const char * path, const char *filename, const char *parent, const char *type ) {
     // Serial.printf("Appending to file: %s\n", path);
-    snprintf(logBuf, serialLoglength, "Listing directory: %s\n", filename);
+    snprintf(logBuf, serialLoglength, "%s: %s\n", (char *) FPSTR(listingDirectory), filename);
     loggerNl(logBuf, LOGLEVEL_DEBUG);
     File file = fs.open(path, FILE_APPEND);
     // i/o is timing critical keep all stuff running
     esp_task_wdt_reset();
     if (!file) {
-        snprintf(logBuf, serialLoglength, "Failed to open file for appending");
+        snprintf(logBuf, serialLoglength, (char *) FPSTR(failedToOpenFileForAppending));
         loggerNl(logBuf, LOGLEVEL_DEBUG);
         return;
     }
@@ -534,7 +532,8 @@ bool pathValid(const char *_fileItem) {
  * @param parent
  * @param levels
  */
-char fileNameBuf[255];
+//char fileNameBuf[255];
+char *fileNameBuf = (char *) calloc(255, sizeof(char));         // In heap to save static memory
 
 void parseSDFileList(fs::FS &fs, const char * dirname, const char * parent, uint8_t levels) {
     esp_task_wdt_reset();
@@ -543,13 +542,13 @@ void parseSDFileList(fs::FS &fs, const char * dirname, const char * parent, uint
     File root = fs.open(dirname);
 
     if (!root) {
-        snprintf(logBuf, serialLoglength, "Failed to open directory");
+        snprintf(logBuf, serialLoglength, (char *) FPSTR(failedToOpenDirectory));
         loggerNl(logBuf, LOGLEVEL_DEBUG);
         return;
     }
 
     if (!root.isDirectory()) {
-        snprintf(logBuf, serialLoglength, "Not a directory");
+        snprintf(logBuf, serialLoglength, (char *) FPSTR(notADirectory));
         loggerNl(logBuf, LOGLEVEL_DEBUG);
         return;
     }
@@ -568,7 +567,7 @@ void parseSDFileList(fs::FS &fs, const char * dirname, const char * parent, uint
             continue;
         }
 
-        strncpy(fileNameBuf, (char *) file.name(), sizeof(fileNameBuf) / sizeof(fileNameBuf[0]));
+        strncpy(fileNameBuf, (char *) file.name(), 255);
 
         // we have a folder
         if(file.isDirectory()) {
@@ -3163,9 +3162,7 @@ bool processJsonRequest(char *_serialJson) {
         if (s.compareTo(rfidString)) {
             return false;
         }
-        #ifndef SD_NOT_MANDATORY_ENABLE
-            dumpNvsToSd("rfidTags", (char *) FPSTR(backupFile));        // Store backup-file every time when a new rfid-tag is programmed
-        #endif
+        dumpNvsToSd("rfidTags", (char *) FPSTR(backupFile));        // Store backup-file every time when a new rfid-tag is programmed
 
     } else if (doc.containsKey("rfidAssign")) {
         const char *_rfidIdAssinId = object["rfidAssign"]["rfidIdMusic"];
@@ -3181,9 +3178,7 @@ bool processJsonRequest(char *_serialJson) {
         if (s.compareTo(rfidString)) {
             return false;
         }
-        #ifndef SD_NOT_MANDATORY_ENABLE
-            dumpNvsToSd("rfidTags", (char *) FPSTR(backupFile));                     // Store backup-file every time when a new rfid-tag is programmed
-        #endif
+        dumpNvsToSd("rfidTags", (char *) FPSTR(backupFile));                     // Store backup-file every time when a new rfid-tag is programmed
 
     } else if (doc.containsKey("wifiConfig")) {
         const char *_ssid = object["wifiConfig"]["ssid"];
@@ -3221,7 +3216,7 @@ bool processJsonRequest(char *_serialJson) {
     return true;
 }
 
-
+char *jBuf = (char *) calloc(255, sizeof(char));        // In heap to save static memory
 // Sends JSON-answers via websocket
 void sendWebsocketData(uint32_t client, uint8_t code) {
     const size_t CAPACITY = JSON_OBJECT_SIZE(1) + 20;
@@ -3242,8 +3237,9 @@ void sendWebsocketData(uint32_t client, uint8_t code) {
         object["indexingState"] = fileNameBuf;
     }
 
-    char jBuf[255];
-    serializeJson(doc, jBuf, sizeof(jBuf) / sizeof(jBuf[0]));
+    //char jBuf[255];
+
+    serializeJson(doc, jBuf, 255);
 
     if (client == 0) {
         ws.printfAll(jBuf);
@@ -3376,7 +3372,7 @@ void webserverStart(void) {
     });
 
     wServer.on("/files", HTTP_GET, [](AsyncWebServerRequest *request) {
-        request->send(SD, "/files.json", "application/json");
+        request->send(SD, DIRECTORY_INDEX_FILE, "application/json");
     });
 
     wServer.onNotFound(notFound);
@@ -3390,7 +3386,6 @@ void webserverStart(void) {
 
 
 // Dumps all RFID-entries from NVS into a file on SD-card
-#ifndef SD_NOT_MANDATORY_ENABLE
     bool dumpNvsToSd(char *_namespace, char *_destFile) {
         esp_partition_iterator_t pi;                // Iterator for find
         const esp_partition_t* nvs;                 // Pointer to partition struct
@@ -3454,7 +3449,6 @@ void webserverStart(void) {
         backupFile.close();
         return true;
     }
-#endif
 
 
 // Handles uploaded backup-file and writes valid entries into NVS
@@ -3559,9 +3553,6 @@ void setup() {
     #endif
             loggerNl((char *) FPSTR(unableToMountSd), LOGLEVEL_ERROR);
             delay(500);
-            #ifdef SD_NOT_MANDATORY_ENABLE
-                break;
-            #endif
             #ifdef SHUTDOWN_IF_SD_BOOT_FAILS
                 if (millis() >= deepsleepTimeAfterBootFails*1000) {
                     loggerNl((char *) FPSTR(sdBootFailedDeepsleep), LOGLEVEL_ERROR);
diff --git a/src/settings.h b/src/settings.h
index 23e6f87..f4b5fb4 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -13,7 +13,6 @@
 //#define PLAY_LAST_RFID_AFTER_REBOOT // When restarting Tonuino, the last RFID that was active before, is recalled and played
 
 //#define SINGLE_SPI_ENABLE         // If only one SPI-instance should be used instead of two (not yet working!)
-//#define SD_NOT_MANDATORY_ENABLE   // Only for debugging-purposes: Tonuino will also start without mounted SD-card anyway (will only try once to mount it). Will overwrite SHUTDOWN_IF_SD_BOOT_FAILS!
 //#define BLUETOOTH_ENABLE          // Doesn't work currently (so don't enable) as there's not enough DRAM available
 
 
@@ -97,9 +96,7 @@ uint16_t intervalToLongPress = 700;                 // Interval in ms to disting
 static const char accessPointNetworkSSID[] PROGMEM = "Tonuino";     // Access-point's SSID
 
 // Where to store the backup-file for NVS-records
-#ifndef SD_NOT_MANDATORY_ENABLE
-    static const char backupFile[] PROGMEM = "/backup.txt"; // File is written every time a (new) RFID-assignment via GUI is done
-#endif
+static const char backupFile[] PROGMEM = "/backup.txt"; // File is written every time a (new) RFID-assignment via GUI is done
 
 // (webgui) File Browser
 uint8_t FS_DEPTH = 5;                               // Max. recursion-depth of file tree
@@ -152,5 +149,7 @@ float voltageIndicatorHigh = 4.2;                   // Upper range for Neopixel-
     static const char topicRepeatModeState[] PROGMEM = "State/Tonuino/RepeatMode";
     static const char topicLedBrightnessCmnd[] PROGMEM = "Cmnd/Tonuino/LedBrightness";
     static const char topicLedBrightnessState[] PROGMEM = "State/Tonuino/LedBrightness";
-    static const char topicBatteryVoltage[] PROGMEM = "State/Tonuino/Voltage";
+    #ifdef MEASURE_BATTERY_VOLTAGE
+        static const char topicBatteryVoltage[] PROGMEM = "State/Tonuino/Voltage";
+    #endif
 #endif