diff --git a/internal/api/cameras.go b/internal/api/cameras.go
index 261720b..755adca 100644
--- a/internal/api/cameras.go
+++ b/internal/api/cameras.go
@@ -26,12 +26,12 @@ func ListCameras(database *db.DB) http.HandlerFunc {
 				c.friendly_name,
 				s.battery_pct,
 				s.video_remaining_sec,
-				s.recording_state,
+				COALESCE(s.recording_state, 0),
 				s.mode,
 				s.resolution,
 				s.fps,
-				s.online,
-				s.recorded_at
+				COALESCE(s.online, 0),
+				COALESCE(s.recorded_at, c.created_at)
 			FROM cameras c
 			LEFT JOIN (
 				SELECT camera_id, battery_pct, video_remaining_sec, recording_state,
diff --git a/internal/mqtt/subscriber.go b/internal/mqtt/subscriber.go
index 7c274d0..abe5cf8 100644
--- a/internal/mqtt/subscriber.go
+++ b/internal/mqtt/subscriber.go
@@ -282,10 +282,12 @@ func (s *Subscriber) handleStatus(cameraID string, payload []byte) {
 // ── Heartbeat handler ───────────────────────────────────────────────────
 
 type heartbeatPayload struct {
-	CameraID  string `json:"camera_id"`
-	Timestamp string `json:"timestamp"`
-	UptimeSec *int   `json:"uptime_sec"`
-	FreeHeap  *int   `json:"free_heap"`
+	CameraID string `json:"camera_id"`
+	// No Timestamp field: the node sends a numeric millis() value and the
+	// handler doesn't use it; omitting the field lets it be ignored instead
+	// of failing JSON unmarshal (number into string).
+	UptimeSec *int `json:"uptime_sec"`
+	FreeHeap  *int `json:"free_heap"`
 }
 
 func (s *Subscriber) handleHeartbeat(cameraID string, payload []byte) {
@@ -360,8 +362,8 @@ func (s *Subscriber) handleAnnounce(cameraID string, payload []byte) {
 		"SELECT camera_id FROM cameras WHERE mac_address = ?", ap.MacAddress,
 	).Scan(&existingID)
 
-	if err == nil {
-		// Already registered — just update friendly_name
+	if err == nil && existingID == cameraID {
+		// Same self-id re-connecting — just refresh friendly_name.
 		_, err = s.db.Exec(
 			"UPDATE cameras SET friendly_name = ?, updated_at = datetime('now') WHERE camera_id = ?",
 			ap.FriendlyName, existingID,
@@ -372,6 +374,12 @@ func (s *Subscriber) handleAnnounce(cameraID string, payload []byte) {
 		}
 		log.Printf("MQTT announce: camera %s (%s) re-connected", existingID, ap.FriendlyName)
 	} else {
+		// MAC known under a different id (legacy cam-NNN from before self-IDs)
+		// → drop the old row so we re-register under the node's self-id.
+		if err == nil && existingID != cameraID {
+			s.db.Exec("DELETE FROM cameras WHERE camera_id = ?", existingID)
+			log.Printf("MQTT announce: migrating %s -> %s (%s)", existingID, cameraID, ap.FriendlyName)
+		}
 		// Option B: the node self-assigns its camera_id (the announce topic id).
 		_, err = s.db.Exec(`
 			INSERT INTO cameras (camera_id, friendly_name, mac_address, created_at, updated_at)