diff --git a/src/LoadSecrets.cpp b/src/LoadSecrets.cpp
index 9818266..35f9a1e 100644
--- a/src/LoadSecrets.cpp
+++ b/src/LoadSecrets.cpp
@@ -32,6 +32,7 @@
 // History:
 //
 // 20240815 Copied from BresserWeatherSensorLW
+// 20241002 Refactoring & modification for LoRaWAN v1.0.4 (requires no nwkKey)
 //
 // ToDo:
 // -
@@ -41,7 +42,7 @@
 #include "LoadSecrets.h"
 
 // Load LoRaWAN secrets from file 'secrets.json' on LittleFS, if available
-void loadSecrets(uint64_t &joinEUI, uint64_t &devEUI, uint8_t *nwkKey, uint8_t *appKey)
+void loadSecrets(bool requireNwkKey, uint64_t &joinEUI, uint64_t &devEUI, uint8_t *nwkKey, uint8_t *appKey)
 {
 
   if (!LittleFS.begin(
@@ -52,147 +53,147 @@ void loadSecrets(uint64_t &joinEUI, uint64_t &devEUI, uint8_t *nwkKey, uint8_t *
           ))
   {
     log_d("Could not initialize LittleFS.");
+    return;
   }
-  else
+
+  File file = LittleFS.open("/secrets.json", "r");
+
+  if (!file)
+  {
+    log_i("File 'secrets.json' not found.");
+    return;
+  }
+
+  log_d("Reading 'secrets.json'");
+  JsonDocument doc;
+
+  // Deserialize the JSON document
+  DeserializationError error = deserializeJson(doc, file);
+  file.close();
+
+  if (error)
+  {
+    log_d("Failed to read JSON file, using defaults.");
+    return;
+  }
+
+  const char *joinEUIStr = doc["joinEUI"];
+  if (joinEUIStr == nullptr)
+  {
+    log_e("Missing joinEUI.");
+    return;
+  }
+
+  uint64_t _joinEUI = 0;
+  for (int i = 2; i < 18; i += 2)
+  {
+    char tmpStr[3] = "";
+    unsigned int tmpByte;
+    strncpy(tmpStr, &joinEUIStr[i], 2);
+    sscanf(tmpStr, "%x", &tmpByte);
+    _joinEUI = (_joinEUI << 8) | tmpByte;
+  }
+  // printf() cannot print 64-bit hex numbers (sic!), so we split it in two 32-bit numbers...
+  log_d("joinEUI: 0x%08X%08X", static_cast<uint32_t>(_joinEUI >> 32), static_cast<uint32_t>(_joinEUI & 0xFFFFFFFF));
+
+  const char *devEUIStr = doc["devEUI"];
+  if (devEUIStr == nullptr)
   {
-    File file = LittleFS.open("/secrets.json", "r");
+    log_e("Missing devEUI.");
+    return;
+  }
+
+  uint64_t _devEUI = 0;
+  for (int i = 2; i < 18; i += 2)
+  {
+    char tmpStr[3] = "";
+    unsigned int tmpByte;
+    strncpy(tmpStr, &devEUIStr[i], 2);
+    sscanf(tmpStr, "%x", &tmpByte);
+    _devEUI = (_devEUI << 8) | tmpByte;
+  }
+  if (_devEUI == 0)
+  {
+    log_e("devEUI is zero.");
+    return;
+  }
+  // printf() cannot print 64-bit hex numbers (sic!), so we split it in two 32-bit numbers...
+  log_d("devEUI: 0x%08X%08X", static_cast<uint32_t>(_devEUI >> 32), static_cast<uint32_t>(_devEUI & 0xFFFFFFFF));
 
-    if (!file)
+  uint8_t check = 0;
+  bool fail = false;
+
+  log_i("appKey:");
+  uint8_t _appKey[16];
+  for (size_t i = 0; i < 16; i++)
+  {
+    const char *buf = doc["appKey"][i];
+    if (buf == nullptr)
     {
-      log_i("File 'secrets.json' not found.");
+      fail = true;
+      break;
     }
-    else
-    {
-      log_d("Reading 'secrets.json'");
-      JsonDocument doc;
-
-      // Deserialize the JSON document
-      DeserializationError error = deserializeJson(doc, file);
-      if (error)
-      {
-        log_d("Failed to read JSON file, using defaults.");
-      }
-      else
-      {
-        const char *joinEUIStr = doc["joinEUI"];
-        if (joinEUIStr == nullptr)
-        {
-          log_e("Missing joinEUI.");
-          file.close();
-          return;
-        }
-        uint64_t _joinEUI = 0;
-        for (int i = 2; i < 18; i += 2)
-        {
-          char tmpStr[3] = "";
-          unsigned int tmpByte;
-          strncpy(tmpStr, &joinEUIStr[i], 2);
-          sscanf(tmpStr, "%x", &tmpByte);
-          _joinEUI = (_joinEUI << 8) | tmpByte;
-        }
-        // printf() cannot print 64-bit hex numbers (sic!), so we split it in two 32-bit numbers...
-        log_d("joinEUI: 0x%08X%08X", static_cast<uint32_t>(_joinEUI >> 32), static_cast<uint32_t>(_joinEUI & 0xFFFFFFFF));
-
-        const char *devEUIStr = doc["devEUI"];
-        if (devEUIStr == nullptr)
-        {
-          log_e("Missing devEUI.");
-          file.close();
-          return;
-        }
-        uint64_t _devEUI = 0;
-        for (int i = 2; i < 18; i += 2)
-        {
-          char tmpStr[3] = "";
-          unsigned int tmpByte;
-          strncpy(tmpStr, &devEUIStr[i], 2);
-          sscanf(tmpStr, "%x", &tmpByte);
-          _devEUI = (_devEUI << 8) | tmpByte;
-        }
-        if (_devEUI == 0)
-        {
-          log_e("devEUI is zero.");
-          file.close();
-          return;
-        }
-        // printf() cannot print 64-bit hex numbers (sic!), so we split it in two 32-bit numbers...
-        log_d("devEUI: 0x%08X%08X", static_cast<uint32_t>(_devEUI >> 32), static_cast<uint32_t>(_devEUI & 0xFFFFFFFF));
-
-        uint8_t check = 0;
-        bool fail = false;
-
-        log_d("nwkKey:");
-        uint8_t _nwkKey[16];
-        for (size_t i = 0; i < 16; i++)
-        {
-          const char *buf = doc["nwkKey"][i];
-          if (buf == nullptr)
-          {
-            fail = true;
-            break;
-          }
-          unsigned int tmp;
-          sscanf(buf, "%x", &tmp);
-          _nwkKey[i] = static_cast<uint8_t>(tmp);
-          check |= _nwkKey[i];
+    unsigned int tmp;
+    sscanf(buf, "%x", &tmp);
+    _appKey[i] = static_cast<uint8_t>(tmp);
+    check |= _appKey[i];
 #if CORE_DEBUG_LEVEL >= ARDUHAL_LOG_LEVEL_INFO
-          printf("0x%02X", _nwkKey[i]);
-          if (i < 15)
-          {
-            printf(", ");
-          }
+    printf("0x%02X", _appKey[i]);
+    if (i < 15)
+    {
+      printf(", ");
+    }
 #endif
-        } // for all nwk_key bytes
+  } // for all app_key bytes
 #if CORE_DEBUG_LEVEL >= ARDUHAL_LOG_LEVEL_INFO
-        printf("\n");
+  printf("\n");
 #endif
-        if (fail || (check == 0))
-        {
-          log_e("nwkKey parse error");
-          file.close();
-          return;
-        }
-
-        check = 0;
-        log_i("appKey:");
-        uint8_t _appKey[16];
-        for (size_t i = 0; i < 16; i++)
-        {
-          const char *buf = doc["appKey"][i];
-          if (buf == nullptr)
-          {
-            fail = true;
-            break;
-          }
-          unsigned int tmp;
-          sscanf(buf, "%x", &tmp);
-          _appKey[i] = static_cast<uint8_t>(tmp);
-          check |= _appKey[i];
+  if (fail || (check == 0))
+  {
+    log_e("appKey parse error");
+    return;
+  }
+
+  check = 0;
+  if (requireNwkKey)
+  {
+    log_d("nwkKey:");
+    uint8_t _nwkKey[16];
+    for (size_t i = 0; i < 16; i++)
+    {
+      const char *buf = doc["nwkKey"][i];
+      if (buf == nullptr)
+      {
+        fail = true;
+        break;
+      }
+      unsigned int tmp;
+      sscanf(buf, "%x", &tmp);
+      _nwkKey[i] = static_cast<uint8_t>(tmp);
+      check |= _nwkKey[i];
 #if CORE_DEBUG_LEVEL >= ARDUHAL_LOG_LEVEL_INFO
-          printf("0x%02X", _appKey[i]);
-          if (i < 15)
-          {
-            printf(", ");
-          }
+      printf("0x%02X", _nwkKey[i]);
+      if (i < 15)
+      {
+        printf(", ");
+      }
 #endif
-        } // for all app_key bytes
+    } // for all nwk_key bytes
 #if CORE_DEBUG_LEVEL >= ARDUHAL_LOG_LEVEL_INFO
-        printf("\n");
+    printf("\n");
 #endif
-        if (fail || (check == 0))
-        {
-          log_e("appKey parse error");
-          file.close();
-          return;
-        }
-
-        // Every check passed, copy intermediate values as result
-        joinEUI = _joinEUI;
-        devEUI = _devEUI;
-        memcpy(nwkKey, _nwkKey, 16);
-        memcpy(appKey, _appKey, 16);
-      } // deserializeJson o.k.
-    } // file read o.k.
-    file.close();
-  } // LittleFS o.k.
+    if (fail || (check == 0))
+    {
+      log_e("nwkKey parse error");
+      return;
+    }
+    memcpy(nwkKey, _nwkKey, 16);
+  } // if (requireNwkKey)
+
+  // Every check passed, copy intermediate values as result
+  joinEUI = _joinEUI;
+  devEUI = _devEUI;
+  memcpy(appKey, _appKey, 16);
+
+  return;
 }
diff --git a/src/LoadSecrets.h b/src/LoadSecrets.h
index 9cef6a0..e17d6a9 100644
--- a/src/LoadSecrets.h
+++ b/src/LoadSecrets.h
@@ -32,6 +32,7 @@
 // History:
 //
 // 20240815 Copied from BresserWeatherSensorLW
+// 20241002 Refactoring & modification for LoRaWAN v1.0.4 (requires no nwkKey)
 //
 // ToDo:
 // -
@@ -51,9 +52,10 @@
  * Use https://github.com/earlephilhower/arduino-littlefs-upload for uploading
  * the file to Flash.
  *
+ * \param requireNwkKey
  * \param joinEUI
  * \param devEUI
  * \param nwkKey
  * \param appKey
  */
-void loadSecrets(uint64_t &joinEUI, uint64_t &devEUI, uint8_t *nwkKey, uint8_t *appKey);
\ No newline at end of file
+void loadSecrets(bool requireNwkKey, uint64_t &joinEUI, uint64_t &devEUI, uint8_t *nwkKey, uint8_t *appKey);
\ No newline at end of file