diff --git a/src/main.cpp b/src/main.cpp
index f01adc2..65cd03c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -437,7 +437,7 @@ static void handleRoot() {
     meterRows += "<div class=tabs><div class=tab-nav>";
     for (int i = 0; i < meterCount; i++) {
       String label = strlen(meters[i].name) > 0 ? escHtml(meters[i].name) : "Meter " + String(i);
-      meterRows += "<button class=tab-btn" + String(i == 0 ? " active" : "") + " data-tab=" + String(i) + ">" + label + "</button>";
+      meterRows += "<button type=button class=tab-btn" + String(i == 0 ? " active" : "") + " data-tab=" + String(i) + ">" + label + "</button>";
     }
     meterRows += "</div>";
   }
@@ -816,6 +816,11 @@ static void applyFactoryResetIfNeeded(int count) {
 void setup() {
   Serial.begin(115200);
   Serial.println("\n\n=== M1730 boot ===");
+  Serial.printf("[BOOT] chip=%s rev=%d cores=%d cpu=%dMHz flash=%uMB\n",
+                ESP.getChipModel(), ESP.getChipRevision(), ESP.getChipCores(),
+                ESP.getCpuFreqMHz(), ESP.getFlashChipSize() / (1024 * 1024));
+  Serial.printf("[BOOT] free heap=%u sketch=%u / %u\n",
+                ESP.getFreeHeap(), ESP.getSketchSize(), ESP.getFreeSketchSpace());
   if (!LittleFS.begin(false)) {
     Serial.println("[FS] mount failed, formatting...");
     LittleFS.begin(true);
@@ -829,6 +834,14 @@ void setup() {
   loadConfig();
   hostnameParam.setValue(hostname, sizeof(hostname) - 1);
 
+  for (int i = 0; i < meterCount; i++)
+    Serial.printf("[BOOT] meter[%d] pin=%d name=\"%s\" unit=\"%s\" maxD=%.1f range=[%.1f,%.1f] cur=%.1f\n",
+                  i, meters[i].pin, meters[i].name, meters[i].unit,
+                  meters[i].maxDuty, meters[i].rangeMin, meters[i].rangeMax, meters[i].currentValue);
+  Serial.printf("[BOOT] mqtt=%d broker=%s:%d prefix=%s\n",
+                mqttCfg.enabled, mqttCfg.host, mqttCfg.port, mqttCfg.prefix);
+  Serial.printf("[BOOT] auth=%d\n", authCfg.enabled);
+
   int resetCount = incrementResetCount();
 
   attachMeters();
@@ -854,7 +867,8 @@ void setup() {
     Serial.println("[WIFI] failed, restarting");
     ESP.restart();
   }
-  Serial.printf("[WIFI] connected, IP: %s\n", WiFi.localIP().toString().c_str());
+  Serial.printf("[WIFI] connected, IP: %s MAC: %s RSSI: %d\n",
+                WiFi.localIP().toString().c_str(), WiFi.macAddress().c_str(), WiFi.RSSI());
 
   strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
   saveConfig();
@@ -864,6 +878,7 @@ void setup() {
 
   Serial.printf("[BOOT] ready at http://%s.local or http://%s\n",
                 hostname, WiFi.localIP().toString().c_str());
+  Serial.printf("[BOOT] free heap=%u\n", ESP.getFreeHeap());
 }
 
 void loop() {