diff --git a/MQTT_IMPLEMENTATION.md b/MQTT_IMPLEMENTATION.md
index 681af98b3..32fec249a 100644
--- a/MQTT_IMPLEMENTATION.md
+++ b/MQTT_IMPLEMENTATION.md
@@ -606,6 +606,7 @@ These settings apply across all MQTT slots:
 - `get mqtt.packets` - Get packet message setting (on/off)
 - `get mqtt.raw` - Get raw message setting (on/off)
 - `get mqtt.rx` - Get RX packet uplinking setting (on/off)
+- `get mqtt.advert.verify` - Get advert signature filtering setting (on/off)
 - `get mqtt.tx` - Get TX packet uplinking setting (on/off/advert)
 - `get mqtt.interval` - Get status publish interval
 - `get mqtt.neighbors` - Get periodic neighbors publishing setting (on/off; neighbors-enabled builds)
@@ -622,6 +623,7 @@ These settings apply across all MQTT slots:
 - `set mqtt.packets on|off` - Enable/disable packet messages
 - `set mqtt.raw on|off` - Enable/disable raw messages
 - `set mqtt.rx on|off` - Enable/disable RX (received) packet uplinking
+- `set mqtt.advert.verify on|off` - Skip received adverts whose signature fails (default off)
 - `set mqtt.tx on|off|advert` - Set TX packet uplinking mode:
   - `on` - Uplink all transmitted packets
   - `advert` - Uplink only this node's own advert packets (self-originated)
diff --git a/docs/cli_commands.md b/docs/cli_commands.md
index 39d19ccbf..d468e43d0 100644
--- a/docs/cli_commands.md
+++ b/docs/cli_commands.md
@@ -5213,6 +5213,29 @@ USB logging remains independent. On images with both outputs,
 
 ---
 
+#### View or change MQTT advert signature filtering
+
+**Usage:**
+
+- `get mqtt.advert.verify`
+- `set mqtt.advert.verify <on|off>`
+
+**Parameters:**
+
+- `on`: verify the Ed25519 signature of each received advert and skip publishing any that fail (the same check the mesh applies before relaying)
+- `off`: publish received adverts as heard
+
+**Default:** `off`
+
+> **Note:** Adverts are uploaded before the mesh validates them, so a frame corrupted over the air that still passes the LoRa CRC is published with a mangled name or location. Leaving this off keeps that corruption visible to collectors; turning it on hides it from them. Dropped adverts are counted as `badsig=` in `get mqtt.stats`. Takes effect immediately.
+
+On Companion builds, enabling this setting opts into a marked MQTT preference
+record. Before rolling back to firmware without this setting, turn it off to
+restore the older record format and retain the saved MQTT setup. Ordinary
+default-off updates keep the existing record size.
+
+---
+
 #### View or change periodic neighbors publishing (MQTT observer, neighbors feature)
 **Usage:**
 - `get mqtt.neighbors`
diff --git a/examples/companion_radio/MyMesh.cpp b/examples/companion_radio/MyMesh.cpp
index 07f459b04..a692c665d 100644
--- a/examples/companion_radio/MyMesh.cpp
+++ b/examples/companion_radio/MyMesh.cpp
@@ -5189,6 +5189,7 @@ void MyMesh::execCommand(char* cmd, char* reply) {
     else if (strcmp(key, "mqtt.packets") == 0) value = _mqtt_prefs.mqtt_packets_enabled ? "on" : "off";
     else if (strcmp(key, "mqtt.raw") == 0) value = _mqtt_prefs.mqtt_raw_enabled ? "on" : "off";
     else if (strcmp(key, "mqtt.rx") == 0) value = _mqtt_prefs.mqtt_rx_enabled ? "on" : "off";
+    else if (strcmp(key, "mqtt.advert.verify") == 0) value = _mqtt_prefs.mqtt_advert_verify ? "on" : "off";
     else if (strcmp(key, "mqtt.tx") == 0) value = _mqtt_prefs.mqtt_tx_enabled == 2 ? "advert" : _mqtt_prefs.mqtt_tx_enabled ? "on" : "off";
     else if (strcmp(key, "mqtt.ntp") == 0) value = _mqtt_prefs.mqtt_ntp_server;
     else if (strcmp(key, "mqtt.owner") == 0) value = _mqtt_prefs.mqtt_owner_public_key;
@@ -5459,6 +5460,7 @@ void MyMesh::execCommand(char* cmd, char* reply) {
     }
   } else if (strcmp(key, "mqtt.status") == 0 || strcmp(key, "mqtt.packets") == 0
              || strcmp(key, "mqtt.raw") == 0 || strcmp(key, "mqtt.rx") == 0
+             || strcmp(key, "mqtt.advert.verify") == 0
              || strcmp(key, "snmp") == 0) {
     bool enabled;
     if (!wcParseBool(value, enabled)) {
@@ -5469,6 +5471,7 @@ void MyMesh::execCommand(char* cmd, char* reply) {
     else if (strcmp(key, "mqtt.packets") == 0) _mqtt_prefs.mqtt_packets_enabled = enabled;
     else if (strcmp(key, "mqtt.raw") == 0) _mqtt_prefs.mqtt_raw_enabled = enabled;
     else if (strcmp(key, "mqtt.rx") == 0) _mqtt_prefs.mqtt_rx_enabled = enabled;
+    else if (strcmp(key, "mqtt.advert.verify") == 0) _mqtt_prefs.mqtt_advert_verify = enabled;
     else _mqtt_prefs.snmp_enabled = enabled;
     changed = true;
   } else if (strcmp(key, "mqtt.tx") == 0) {
diff --git a/examples/simple_repeater/MyMesh.cpp b/examples/simple_repeater/MyMesh.cpp
index 6d94128a3..83695245c 100644
--- a/examples/simple_repeater/MyMesh.cpp
+++ b/examples/simple_repeater/MyMesh.cpp
@@ -3436,8 +3436,8 @@ bool MyMesh::onPeerPathRecv(mesh::Packet *packet, int sender_idx, const uint8_t
 void MyMesh::onControlDataRecv(mesh::Packet* packet) {
   uint8_t type = packet->payload[0] & 0xF0;    // just test upper 4 bits
   if (type == CTL_TYPE_NODE_DISCOVER_REQ && packet->payload_len >= 6
-      && discover_limiter.allow(rtc_clock.getCurrentTime())
       && !isHiddenNode()   // this node wishes to NOT be discoverable
+      && discover_limiter.allow(rtc_clock.getCurrentTime())
   ) {
     int i = 1;
     uint8_t  filter = packet->payload[i++];
diff --git a/scripts/webconfig_mock_server.py b/scripts/webconfig_mock_server.py
index c346e9dbb..c9461d180 100644
--- a/scripts/webconfig_mock_server.py
+++ b/scripts/webconfig_mock_server.py
@@ -121,7 +121,7 @@ def default_config(setup_mode):
         "mqtt": {
             "enabled": False,
             "origin": "" if setup_mode else "MockNode", "iata": "" if setup_mode else "DEN",
-            "status": True, "packets": True, "raw": False, "tx": "advert", "rx": True,
+            "status": True, "packets": True, "raw": False, "tx": "advert", "rx": True, "advert_verify": False,
             "interval": 5, "timezone": "MST7MDT,M3.2.0,M11.1.0", "timezone_offset": -7,
             "ntp": "pool.ntp.org", "owner": "", "email": "", "snmp": False,
             "snmp_community": "public",
@@ -228,7 +228,8 @@ BOOL_KEYS = {"mqtt.enabled": ("mqtt", "enabled"), "cad": ("radio", "cad"), "radi
              "powersaving": ("radio", "powersaving"),
              "repeat": ("radio", "repeat"), "mqtt.status": ("mqtt", "status"),
              "mqtt.packets": ("mqtt", "packets"), "mqtt.raw": ("mqtt", "raw"),
-             "mqtt.rx": ("mqtt", "rx"), "snmp": ("mqtt", "snmp"),
+             "mqtt.rx": ("mqtt", "rx"), "mqtt.advert.verify": ("mqtt", "advert_verify"),
+             "snmp": ("mqtt", "snmp"),
              "mqtt.neighbors": ("mqtt", "neighbors")}
 INT_KEYS = {"tx": ("radio", "tx"), "flood.max": ("radio", "flood_max"),
             "flood.max.advert": ("radio", "flood_max_advert"),
diff --git a/src/helpers/AdvertSignature.h b/src/helpers/AdvertSignature.h
new file mode 100644
index 000000000..3dc4bf2fe
--- /dev/null
+++ b/src/helpers/AdvertSignature.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+#include <MeshCore.h>
+
+// Signed-message layout of an ADVERT payload, mirroring Mesh::onRecvPacket:
+// pub_key(32) + timestamp(4) + signature(64) + app_data. Oversized app_data is
+// rejected, like Mesh::onRecvPacket: truncation would accept an unsigned tail.
+namespace AdvertSignature {
+
+static const int kHeaderLen = PUB_KEY_SIZE + 4 + SIGNATURE_SIZE;
+static const int kMaxMessageLen = PUB_KEY_SIZE + 4 + MAX_ADVERT_DATA_SIZE;
+
+// Builds the signed message into `out` (kMaxMessageLen bytes) and points `sig`
+// at the signature. Returns the message length, or -1 for invalid arguments or
+// a payload outside the complete signed advert layout. Clears sig on failure.
+static inline int buildMessage(const uint8_t* payload, int payload_len,
+                               uint8_t* out, const uint8_t** sig) {
+  if (sig == nullptr) return -1;
+  *sig = nullptr;
+  if (payload == nullptr || out == nullptr || payload_len < kHeaderLen ||
+      payload_len > kHeaderLen + MAX_ADVERT_DATA_SIZE) return -1;
+  int app_data_len = payload_len - kHeaderLen;
+  memcpy(out, payload, PUB_KEY_SIZE + 4);
+  memcpy(out + PUB_KEY_SIZE + 4, payload + kHeaderLen, app_data_len);
+  *sig = payload + PUB_KEY_SIZE + 4;
+  return PUB_KEY_SIZE + 4 + app_data_len;
+}
+
+}  // namespace AdvertSignature
diff --git a/src/helpers/CommonCLI.cpp b/src/helpers/CommonCLI.cpp
index 4b0deff4c..f330652e9 100644
--- a/src/helpers/CommonCLI.cpp
+++ b/src/helpers/CommonCLI.cpp
@@ -2776,11 +2776,11 @@ void CommonCLI::loadMQTTPrefs(
   if (MQTTPrefsCodec::repairDisplayPrefs(&_mqtt_prefs)) {
     // Old payloads retain valid defaults because the object was defaulted before
     // their shorter prefix was copied. This branch repairs only a full/newer
-    // payload carrying invalid display values.
+    // payload carrying invalid display or advert-verification values.
     if (!_mqtt_prefs_hold) {
       mqtt_rewrite_pending = true;
     }
-    MESH_DEBUG_PRINTLN("MQTT: invalid display preferences reset to defaults");
+    MESH_DEBUG_PRINTLN("MQTT: invalid display/advert preferences reset to defaults");
   }
   _legacy_tail.valid = false;
 
diff --git a/src/helpers/CommonCLI_Observer.cpp b/src/helpers/CommonCLI_Observer.cpp
index b6e72ea05..68347c597 100644
--- a/src/helpers/CommonCLI_Observer.cpp
+++ b/src/helpers/CommonCLI_Observer.cpp
@@ -330,6 +330,19 @@ bool CommonCLI::handleObserverSetCmd(uint32_t sender_timestamp, const char* conf
     _mqtt_prefs.mqtt_rx_enabled = memcmp(&config[8], "on", 2) == 0 ? 1 : 0;
     saveObserverPrefs();
     strcpy(reply, "OK");
+  } else if (memcmp(config, "mqtt.advert.verify ", 19) == 0) {
+    if (strcmp(config + 19, "on") != 0 && strcmp(config + 19, "off") != 0) {
+      strcpy(reply, "Error: must be on or off");
+      return true;
+    }
+    const uint8_t previous = _mqtt_prefs.mqtt_advert_verify;
+    _mqtt_prefs.mqtt_advert_verify = strcmp(config + 19, "on") == 0;
+    if (!saveObserverPrefs()) {
+      _mqtt_prefs.mqtt_advert_verify = previous;
+      strcpy(reply, "Error: settings could not be saved");
+      return true;
+    }
+    strcpy(reply, "OK");
   } else if (memcmp(config, "mqtt.interval ", 14) == 0) {
     uint32_t minutes = _atoi(&config[14]);
     if (minutes >= 1 && minutes <= 60) {
@@ -956,6 +969,8 @@ bool CommonCLI::handleObserverGetCmd(uint32_t sender_timestamp, const char* conf
     sprintf(reply, "> %s", tx_str);
   } else if (memcmp(config, "mqtt.rx", 7) == 0) {
     sprintf(reply, "> %s", _mqtt_prefs.mqtt_rx_enabled ? "on" : "off");
+  } else if (strcmp(config, "mqtt.advert.verify") == 0) {
+    sprintf(reply, "> %s", _mqtt_prefs.mqtt_advert_verify ? "on" : "off");
   } else if (memcmp(config, "mqtt.interval", 13) == 0) {
     uint32_t minutes = (_mqtt_prefs.mqtt_status_interval + 29999) / 60000;
     sprintf(reply, "> %u minutes (%lu ms)", minutes, (unsigned long)_mqtt_prefs.mqtt_status_interval);
diff --git a/src/helpers/CompanionMqttPrefsNvs.h b/src/helpers/CompanionMqttPrefsNvs.h
index ad20b27fc..f4c63fed2 100644
--- a/src/helpers/CompanionMqttPrefsNvs.h
+++ b/src/helpers/CompanionMqttPrefsNvs.h
@@ -9,8 +9,10 @@
 
 // The ESP32 Companion setup portal stores a raw MQTTPrefs blob in NVS rather
 // than the observer's versioned /mqtt_prefs file. Display preferences are not
-// used by Companion firmware, so keep writing the last pre-display boundary:
-// older firmware can then read a record saved by a newer image after rollback.
+// used by Companion firmware. With advert verification off, keep writing the
+// last pre-display boundary so rollback preserves a normally configured node.
+// Enabling verification opts into a separately marked blob: an old recovery
+// record's former padding must never silently enable a new packet filter.
 namespace CompanionMqttPrefsNvs {
 
 static constexpr size_t kWriteSize = MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE;
@@ -20,10 +22,24 @@ static constexpr size_t kWriteSize = MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE;
 static constexpr size_t kRecoverySize = 2880;
 static_assert(sizeof(MQTTPrefs) >= kRecoverySize,
               "MQTTPrefs no longer contains the recoverable NVS prefix");
+static constexpr size_t kVerifiedSize = 2881;
+static constexpr uint8_t kVerifiedMarker = 0xa7;
+struct Record {
+  MQTTPrefs prefs;
+  uint8_t marker;
+};
+static_assert(offsetof(Record, marker) == kRecoverySize,
+              "the marked NVS blob must append exactly one format byte");
+static_assert(sizeof(Record) >= kVerifiedSize,
+              "the marked NVS record must contain its whole serialized blob");
+
+inline size_t writeSizeFor(const MQTTPrefs& prefs) {
+  return prefs.mqtt_advert_verify != 0 ? kVerifiedSize : kWriteSize;
+}
 
 inline bool accepts(uint16_t version, size_t length) {
   return version == MQTT_PREFS_VERSION
-      && (length == kWriteSize || length == kRecoverySize);
+      && (length == kWriteSize || length == kRecoverySize || length == kVerifiedSize);
 }
 
 }  // namespace CompanionMqttPrefsNvs
diff --git a/src/helpers/CompanionMqttSetupPortal.cpp b/src/helpers/CompanionMqttSetupPortal.cpp
index 5a2689cb7..814d4c054 100644
--- a/src/helpers/CompanionMqttSetupPortal.cpp
+++ b/src/helpers/CompanionMqttSetupPortal.cpp
@@ -594,12 +594,20 @@ bool CompanionMqttSetupPortal::loadStoredConfig(MQTTPrefs& prefs) {
   // default its append-only display tail so adding observer UI preferences
   // cannot discard an existing Companion MQTT setup after an update.
   const bool shape_ok = CompanionMqttPrefsNvs::accepts(version, length);
-  MQTTPrefs loaded;
+  CompanionMqttPrefsNvs::Record record = {};
+  MQTTPrefs& loaded = record.prefs;
   applyMQTTDefaults(&loaded);
-  const size_t read = shape_ok ? nvs.getBytes(NVS_PREFS_KEY, &loaded, length) : 0;
+  const size_t read = shape_ok ? nvs.getBytes(NVS_PREFS_KEY, &record, length) : 0;
   nvs.end();
   if (!shape_ok || read != length) return false;
 
+  // The old 2880-byte recovery blob ended with unspecified padding, including
+  // potentially 1. Only an explicitly marked new blob can opt into filtering.
+  // Invalid optional metadata must not discard otherwise valid credentials.
+  if (length != CompanionMqttPrefsNvs::kVerifiedSize ||
+      record.marker != CompanionMqttPrefsNvs::kVerifiedMarker ||
+      loaded.mqtt_advert_verify > 1) loaded.mqtt_advert_verify = 0;
+
   if (!storedStringsAreValid(loaded)
       || loaded.mqtt_status_enabled > 1
       || loaded.mqtt_packets_enabled > 1
@@ -663,15 +671,20 @@ bool CompanionMqttSetupPortal::saveEnabled(bool enabled) {
 bool CompanionMqttSetupPortal::saveStoredConfig(const MQTTPrefs& prefs) {
   Preferences nvs;
   if (!nvs.begin(NVS_NAMESPACE, false)) return false;
-  // Companion does not consume the appended observer display tail. Keeping
-  // this record at the pre-display boundary makes a firmware rollback retain
-  // the MQTT setup. loadStoredConfig() still accepts the briefly written 2880
-  // byte runtime shape so development images remain recoverable.
-  const size_t written = nvs.putBytes(
-      NVS_PREFS_KEY, &prefs, CompanionMqttPrefsNvs::kWriteSize);
+  // Default configuration keeps the rollback-readable pre-display boundary.
+  // Advert verification and its format marker are one atomic NVS blob write,
+  // not separate preference keys that can disagree after power loss.
+  const size_t payload_size = CompanionMqttPrefsNvs::writeSizeFor(prefs);
+  size_t written;
+  if (prefs.mqtt_advert_verify != 0) {
+    const CompanionMqttPrefsNvs::Record record = {prefs, CompanionMqttPrefsNvs::kVerifiedMarker};
+    written = nvs.putBytes(NVS_PREFS_KEY, &record, payload_size);
+  } else {
+    written = nvs.putBytes(NVS_PREFS_KEY, &prefs, payload_size);
+  }
   const size_t version_written = nvs.putUShort(NVS_VERSION_KEY, MQTT_PREFS_VERSION);
   nvs.end();
-  return written == CompanionMqttPrefsNvs::kWriteSize
+  return written == payload_size
       && version_written == sizeof(uint16_t);
 }
 
diff --git a/src/helpers/MQTTDefaults.h b/src/helpers/MQTTDefaults.h
index b2f1c809e..f2f559d9d 100644
--- a/src/helpers/MQTTDefaults.h
+++ b/src/helpers/MQTTDefaults.h
@@ -70,6 +70,7 @@ static inline void applyMQTTDefaults(MQTTPrefs* prefs) {
   prefs->mqtt_raw_enabled = 0;
   prefs->mqtt_tx_enabled = 2;
   prefs->mqtt_rx_enabled = 1;
+  prefs->mqtt_advert_verify = 0;
   prefs->mqtt_status_interval = 300000;
   prefs->wifi_power_save = mesh::wifi::kDefaultPowerSave;
 
diff --git a/src/helpers/MQTTPrefsCodec.h b/src/helpers/MQTTPrefsCodec.h
index 0ea7504e0..4a8e095e8 100644
--- a/src/helpers/MQTTPrefsCodec.h
+++ b/src/helpers/MQTTPrefsCodec.h
@@ -40,21 +40,24 @@ static const size_t kV1PreObserverPayloadSize = MQTT_PREFS_V1_PRE_OBSERVER_PAYLO
 static const size_t kV1PreNeighborsPayloadSize = MQTT_PREFS_V1_PRE_NEIGHBORS_PAYLOAD_SIZE;
 static const size_t kV1PreFilterPayloadSize = MQTT_PREFS_V1_PRE_FILTER_PAYLOAD_SIZE;
 static const size_t kV1PreDisplayPayloadSize = MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE;
+static const size_t kV1PreAdvertPayloadSize = MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE;
 static const size_t kV1BaselinePayloadSize = MQTT_PREFS_V1_FULL_PAYLOAD_SIZE;
 static const size_t kEncodedSize = sizeof(MQTTPrefsHeader) + kV1BaselinePayloadSize;
 
 // Shortest payload length that still round-trips this configuration.
 //
-// The packet-filter and display tails are optional. Their defaults are exactly
+// The packet-filter, display and advert-verification tails are optional. Their
+// defaults are exactly
 // what a decoder supplies when the corresponding tail is missing, so merely
 // upgrading does not lengthen the file. That matters because /mqtt_prefs also
 // carries WiFi credentials: old firmware that cannot read a longer payload can
 // otherwise lose its network configuration after a downgrade. Changing a
-// filter or display control deliberately opts the node into the required tail.
+// filter, display or verification control deliberately opts into its tail.
 inline size_t payloadLenFor(const MQTTPrefs& prefs) {
+  if (prefs.mqtt_advert_verify != 0) return kV1BaselinePayloadSize;
   if (prefs.display_timeout_secs != DISPLAY_TIMEOUT_DEFAULT_SECS ||
       prefs.display_flip != 0) {
-    return kV1BaselinePayloadSize;
+    return kV1PreAdvertPayloadSize;
   }
   return MQTTPacketFilter::allMasksDefault(prefs.mqtt_slot_packet_filter,
                                            MQTT_PREFS_SLOT_COUNT)
@@ -62,7 +65,8 @@ inline size_t payloadLenFor(const MQTTPrefs& prefs) {
       : kV1PreDisplayPayloadSize;
 }
 
-// Clamp the display tail after loading. Returns true when a persisted value was
+// Clamp the optional display/verification tails after loading. Retain the helper
+// name for callers predating advert verification. Returns true when a value was
 // repaired and should be rewritten (unless the source file is being held).
 inline bool repairDisplayPrefs(MQTTPrefs* prefs) {
   if (prefs == nullptr) return false;
@@ -75,6 +79,10 @@ inline bool repairDisplayPrefs(MQTTPrefs* prefs) {
     prefs->display_flip = 0;
     repaired = true;
   }
+  if (prefs->mqtt_advert_verify > 1) {
+    prefs->mqtt_advert_verify = 0;
+    repaired = true;
+  }
   return repaired;
 }
 
@@ -156,6 +164,10 @@ inline DecodePlan classify(const uint8_t* prefix, size_t prefix_read, size_t fil
       if (header.payload_len == kV1BaselinePayloadSize) {
         return {Source::Current, false, false, true, kV1BaselinePayloadSize};
       }
+      if (header.payload_len == kV1PreAdvertPayloadSize) {
+        // Former complete layout. The default keeps advert verification off.
+        return {Source::Current, false, false, true, kV1PreAdvertPayloadSize};
+      }
       if (header.payload_len == kV1PreDisplayPayloadSize) {
         // Written before runtime display controls. Defaults supply timeout and
         // flip while preserving the packet-filter tail.
diff --git a/src/helpers/MQTTPrefsSerializer.h b/src/helpers/MQTTPrefsSerializer.h
index 3073a144b..fea05e688 100644
--- a/src/helpers/MQTTPrefsSerializer.h
+++ b/src/helpers/MQTTPrefsSerializer.h
@@ -203,10 +203,10 @@ class MQTTPrefsSerializer : public ConfigSerializer {
 
   class MqttPrefs : public ConfigSerializer {
     MQTTPrefs* _prefs;
-    int32_t _packets_enabled, _raw_enabled, _tx_enabled, _rx_enabled;
+    int32_t _packets_enabled, _raw_enabled, _tx_enabled, _rx_enabled, _advert_verify;
     char _default_iata[sizeof(MQTTPrefs::mqtt_iata)];
     bool _seen_origin = false, _seen_iata = false, _seen_packets = false;
-    bool _seen_raw = false, _seen_tx = false, _seen_rx = false;
+    bool _seen_raw = false, _seen_tx = false, _seen_rx = false, _seen_advert_verify = false;
     bool _seen_status = false, _seen_neighbors = false, _seen_owner = false;
     bool _seen_slot1 = false, _seen_slot2 = false, _seen_slot3 = false;
     bool _seen_slot4 = false, _seen_slot5 = false, _seen_slot6 = false;
@@ -224,6 +224,7 @@ class MQTTPrefsSerializer : public ConfigSerializer {
       defStrict("raw_enabled", _raw_enabled, _seen_raw);
       defStrict("tx_enabled", _tx_enabled, _seen_tx);
       defStrict("rx_enabled", _rx_enabled, _seen_rx);
+      defStrict("advert_verify", _advert_verify, _seen_advert_verify);
       defStrict("status", _status, _seen_status);
       defStrict("neighbors", _neighbors, _seen_neighbors);
       defStrict("owner", _owner, _seen_owner);
@@ -239,7 +240,8 @@ class MQTTPrefsSerializer : public ConfigSerializer {
               MQTTPrefsPresetValidator preset_valid)
         : _prefs(prefs), _packets_enabled(prefs->mqtt_packets_enabled),
           _raw_enabled(prefs->mqtt_raw_enabled), _tx_enabled(prefs->mqtt_tx_enabled),
-          _rx_enabled(prefs->mqtt_rx_enabled), _status(prefs), _neighbors(prefs),
+          _rx_enabled(prefs->mqtt_rx_enabled), _advert_verify(prefs->mqtt_advert_verify),
+          _status(prefs), _neighbors(prefs),
           _owner(prefs), _slot1(prefs, 0, preset_valid),
           _slot2(prefs, 1, preset_valid), _slot3(prefs, 2, preset_valid),
           _slot4(prefs, 3, preset_valid), _slot5(prefs, 4, preset_valid),
@@ -257,10 +259,12 @@ class MQTTPrefsSerializer : public ConfigSerializer {
       if (_raw_enabled < 0 || _raw_enabled > 1) { _raw_enabled = 0; *repaired = true; }
       if (_tx_enabled < 0 || _tx_enabled > 2) { _tx_enabled = 2; *repaired = true; }
       if (_rx_enabled < 0 || _rx_enabled > 1) { _rx_enabled = 1; *repaired = true; }
+      if (_advert_verify < 0 || _advert_verify > 1) { _advert_verify = 0; *repaired = true; }
       _prefs->mqtt_packets_enabled = static_cast<uint8_t>(_packets_enabled);
       _prefs->mqtt_raw_enabled = static_cast<uint8_t>(_raw_enabled);
       _prefs->mqtt_tx_enabled = static_cast<uint8_t>(_tx_enabled);
       _prefs->mqtt_rx_enabled = static_cast<uint8_t>(_rx_enabled);
+      _prefs->mqtt_advert_verify = static_cast<uint8_t>(_advert_verify);
       if (_prefs->mqtt_iata[0] != '\0') {
         if (!mqttIataValid(_prefs->mqtt_iata)) {
           memcpy(_prefs->mqtt_iata, _default_iata, sizeof(_default_iata));
diff --git a/src/helpers/MQTTPrefsStorage.h b/src/helpers/MQTTPrefsStorage.h
index 6478e3574..e804354a4 100644
--- a/src/helpers/MQTTPrefsStorage.h
+++ b/src/helpers/MQTTPrefsStorage.h
@@ -125,10 +125,13 @@ struct MQTTPrefs {
 
   // Runtime display controls. These are an append-only v1 tail: older payloads
   // stop before them and retain the defaults below. The serialized payload ends
-  // after display_flip at byte 2879; the compiler's final alignment byte is not
-  // part of the on-flash format.
+  // after display_flip at byte 2879 on pre-verification firmware.
   uint16_t display_timeout_secs;
   uint8_t display_flip;
+  // Drop received adverts whose Ed25519 signature fails before publishing.
+  // Append-only v1 tail at byte 2879 (formerly final struct padding). Defaults
+  // off; only enabling verification requires the 2880-byte serialized payload.
+  uint8_t mqtt_advert_verify;
 };
 
 // Neighbor discovery is scheduled with the wrap-safe millis() helpers, whose
@@ -144,7 +147,7 @@ static const uint32_t MQTT_NEIGHBORS_DEFAULT_INTERVAL_MS = MQTT_NEIGHBORS_DEFAUL
 static const uint16_t DISPLAY_TIMEOUT_DEFAULT_SECS = 60;
 static const uint16_t DISPLAY_TIMEOUT_MAX_SECS = 3600;
 
-// Version-1 has five payload layouts this firmware can decode. Never infer a
+// Version-1 has six payload layouts this firmware can decode. Never infer a
 // compatible payload from an arbitrary SHORTER size: raw prefs have no
 // checksum, so a short length has to match a boundary that was really shipped.
 //
@@ -157,18 +160,20 @@ static const uint16_t DISPLAY_TIMEOUT_MAX_SECS = 3600;
 //   - PRE_NEIGHBORS (2860): full observer tail, no neighbors fields yet.
 //   - PRE_FILTER    (2864): neighbors tail, no per-slot packet filters.
 //   - PRE_DISPLAY   (2876): six filter masks, no runtime display controls.
-//   - FULL          (2879): timeout plus flip, excluding final struct padding.
+//   - PRE_ADVERT    (2879): timeout plus flip, excluding final struct padding.
+//   - FULL          (2880): advert verification consumes that former padding.
 //
 // FULL is the maximum written, not the default: MQTTPrefsCodec::payloadLenFor()
 // keeps emitting PRE_FILTER while every slot and display control has its
 // default. A non-default filter writes PRE_DISPLAY; a non-default display
-// control writes FULL. See the rollback note there -- /mqtt_prefs also carries
-// the WiFi credentials.
+// control writes PRE_ADVERT; enabling advert verification writes FULL. See the
+// rollback note there -- /mqtt_prefs also carries the WiFi credentials.
 static const size_t MQTT_PREFS_V1_PRE_OBSERVER_PAYLOAD_SIZE = 2736;
 static const size_t MQTT_PREFS_V1_PRE_NEIGHBORS_PAYLOAD_SIZE = 2860;
 static const size_t MQTT_PREFS_V1_PRE_FILTER_PAYLOAD_SIZE = 2864;
 static const size_t MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE = 2876;
-static const size_t MQTT_PREFS_V1_FULL_PAYLOAD_SIZE = 2879;
+static const size_t MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE = 2879;
+static const size_t MQTT_PREFS_V1_FULL_PAYLOAD_SIZE = 2880;
 
 // /mqtt_prefs starts with a self-describing 8-byte header. Headerless files
 // are deployed legacy layouts and continue to be distinguished by size.
@@ -303,8 +308,13 @@ static_assert(offsetof(MQTTPrefs, mqtt_slot_packet_filter) == MQTT_PREFS_V1_PRE_
 static_assert(offsetof(MQTTPrefs, display_timeout_secs) == MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE,
               "display timeout must begin at the pre-display payload boundary");
 static_assert(offsetof(MQTTPrefs, display_flip) + sizeof(MQTTPrefs::display_flip) ==
-                  MQTT_PREFS_V1_FULL_PAYLOAD_SIZE,
+                  MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE,
               "serialized display tail must end immediately after display_flip");
+static_assert(offsetof(MQTTPrefs, mqtt_advert_verify) == MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE,
+              "advert verification must consume only the former final padding byte");
+static_assert(offsetof(MQTTPrefs, mqtt_advert_verify) + sizeof(MQTTPrefs::mqtt_advert_verify) ==
+                  MQTT_PREFS_V1_FULL_PAYLOAD_SIZE,
+              "serialized advert verification tail must end immediately after its flag");
 static_assert(sizeof(OldMQTTPrefs) == 472, "frozen pre-slot /mqtt_prefs layout changed");
 static_assert(sizeof(PreWifiPowerOldMQTTPrefs) == 472, "frozen pre-WiFi-power /mqtt_prefs layout changed");
 static_assert(offsetof(OldMQTTPrefs, wifi_power_save) == 144,
diff --git a/src/helpers/WebConfigKeys.h b/src/helpers/WebConfigKeys.h
index 9f8020f1b..f75a5aa99 100644
--- a/src/helpers/WebConfigKeys.h
+++ b/src/helpers/WebConfigKeys.h
@@ -29,7 +29,7 @@ static const char* const WC_ALLOWED_SET_KEYS[] = {
   // MQTTPrefs (WiFi / MQTT / misc observer)
   "wifi.ssid", "wifi.pwd", "wifi.powersave", "espnow.channel",
   "mqtt.enabled", "mqtt.origin", "mqtt.iata", "mqtt.status", "mqtt.packets", "mqtt.raw",
-  "mqtt.tx", "mqtt.rx", "mqtt.interval", "mqtt.neighbors", "mqtt.neighbors.interval",
+  "mqtt.tx", "mqtt.rx", "mqtt.advert.verify", "mqtt.interval", "mqtt.neighbors", "mqtt.neighbors.interval",
   "mqtt.ntp", "mqtt.owner", "mqtt.email",
   "timezone", "timezone.offset", "snmp", "snmp.community",
 };
diff --git a/src/helpers/bridges/MQTTBridge.cpp b/src/helpers/bridges/MQTTBridge.cpp
index ee9d471d8..37265fe0b 100644
--- a/src/helpers/bridges/MQTTBridge.cpp
+++ b/src/helpers/bridges/MQTTBridge.cpp
@@ -11,6 +11,7 @@
 #include "../MQTTReplyFormat.h"
 #include "../MQTTRuntimeBufferLifecycle.h"
 #include "../MQTTTopicRouter.h"
+#include "../AdvertSignature.h"
 #include "../TxtDataHelpers.h"
 #include "../UsbLogging.h"
 #include "../WiFiPowerSave.h"
@@ -519,6 +520,14 @@ void MQTTBridge::formatMqttStatsReply(char* buf, size_t bufsize) {
   if (b->_filtered_packets > 0) {
     replyAppendf(buf, bufsize, &pos, " filt=%lu", b->_filtered_packets);
   }
+  // badsig=<n>: RX adverts dropped by mqtt.advert.verify. Omitted while zero.
+  if (b->_bad_sig_adverts > 0) {
+    replyAppendf(buf, bufsize, &pos, " badsig=%lu", b->_bad_sig_adverts);
+  }
+  // down=<n>: ready slots that are not connected. Without this the reply cannot
+  // show an outage at all - sN= counts publishes, and a slot that never connects
+  // never publishes, so its ok freezes and its err stays 0 for the whole outage.
+  // Omitted while zero, like filt=, so a healthy node's reply keeps its length.
   int down = 0;
   for (int i = 0; i < RUNTIME_MQTT_SLOTS; i++) {
     if (MQTTConnectionHealth::isOutageSlot(
@@ -3931,6 +3940,19 @@ void MQTTBridge::onPacketReceived(mesh::Packet *packet) {
     return;
   }
 
+  // Opt-in: drop adverts that fail verification (RF corruption that passed the
+  // LoRa CRC). The observer callback runs before Mesh::onRecvPacket validates
+  // received adverts; its opt-in filter must enforce the same signed layout.
+  if (_obs->mqtt_advert_verify && packet->getPayloadType() == PAYLOAD_TYPE_ADVERT) {
+    uint8_t message[AdvertSignature::kMaxMessageLen];
+    const uint8_t* sig = nullptr;
+    int msg_len = AdvertSignature::buildMessage(packet->payload, packet->payload_len, message, &sig);
+    if (msg_len < 0 || !mesh::Identity(packet->payload).verify(sig, message, msg_len)) {
+      _bad_sig_adverts++;
+      return;
+    }
+  }
+
   // Queue packet for transmission
   queuePacket(packet, false);
 }
diff --git a/src/helpers/bridges/MQTTBridge.h b/src/helpers/bridges/MQTTBridge.h
index 72435672e..2145d6d64 100644
--- a/src/helpers/bridges/MQTTBridge.h
+++ b/src/helpers/bridges/MQTTBridge.h
@@ -423,6 +423,7 @@ private:
   // on Core 1 (radio callbacks), read on Core 0 for `mqtt.stats`; a torn read of
   // a diagnostic counter is harmless, so no atomic is warranted.
   unsigned long _filtered_packets = 0;
+  unsigned long _bad_sig_adverts = 0;  // RX adverts dropped by mqtt.advert.verify
 
   // Status publish retry tracking
   unsigned long _last_status_retry;  // Track last retry attempt (separate from successful publish)
diff --git a/src/helpers/esp32/WebConfigServer.cpp b/src/helpers/esp32/WebConfigServer.cpp
index 68de7e7df..44d5ea52e 100644
--- a/src/helpers/esp32/WebConfigServer.cpp
+++ b/src/helpers/esp32/WebConfigServer.cpp
@@ -2188,6 +2188,7 @@ void WebConfigServer::handleConfigGet(AsyncWebServerRequest* req) {
     mqtt["tx"] = obs->mqtt_tx_enabled == 2 ? "advert"
                  : obs->mqtt_tx_enabled == 1 ? "on" : "off";
     mqtt["rx"] = (bool)obs->mqtt_rx_enabled;
+    mqtt["advert_verify"] = (bool)obs->mqtt_advert_verify;
     mqtt["interval"] = obs->mqtt_status_interval / 60000;
     mqtt["neighbors"] = (bool)obs->mqtt_neighbors_enabled;
     mqtt["neighbors_interval"] = obs->mqtt_neighbors_interval / 3600000UL;
diff --git a/test/test_advert_signature/test_advert_signature.cpp b/test/test_advert_signature/test_advert_signature.cpp
new file mode 100644
index 000000000..7c4cc5929
--- /dev/null
+++ b/test/test_advert_signature/test_advert_signature.cpp
@@ -0,0 +1,90 @@
+#include <gtest/gtest.h>
+
+#include <vector>
+
+#include "helpers/AdvertSignature.h"
+
+namespace {
+
+std::vector<uint8_t> fromHex(const char* hex) {
+  std::vector<uint8_t> out;
+  for (const char* p = hex; p[0] && p[1]; p += 2) {
+    char byte[3] = {p[0], p[1], 0};
+    out.push_back(static_cast<uint8_t>(strtoul(byte, nullptr, 16)));
+  }
+  return out;
+}
+
+// ADVERT payload for "LCC Andice Observer" as heard by a working observer.
+const char* kAdvertPayload =
+    "1EEB3527ED66C732185A2F29264A7450DBA40F1686CAE580F72BC80E65B2D835"
+    "F18EC66A"
+    "1A4FBA70C4BF0A2BCA115F131A6A0F2D54A6E3F8AFCD893F3414DB9DE31EC87E"
+    "AD2D21F54C4C9ED1CD40147F10515BFE47CB83D27B8C20B29BF5B2A61BDA430B"
+    "92FCEFD50106D52AFA4C434320416E64696365204F62736572766572";
+
+}  // namespace
+
+TEST(AdvertSignature, BuildsPubKeyTimestampAndAppData) {
+  std::vector<uint8_t> payload = fromHex(kAdvertPayload);
+  uint8_t message[AdvertSignature::kMaxMessageLen];
+  const uint8_t* sig = nullptr;
+
+  int len = AdvertSignature::buildMessage(payload.data(), static_cast<int>(payload.size()),
+                                          message, &sig);
+
+  int app_data_len = static_cast<int>(payload.size()) - AdvertSignature::kHeaderLen;
+  ASSERT_EQ(PUB_KEY_SIZE + 4 + app_data_len, len);
+  EXPECT_EQ(payload.data() + PUB_KEY_SIZE + 4, sig);
+  EXPECT_EQ(0, memcmp(message, payload.data(), PUB_KEY_SIZE + 4));
+  EXPECT_EQ(0, memcmp(message + PUB_KEY_SIZE + 4, payload.data() + AdvertSignature::kHeaderLen,
+                      app_data_len));
+}
+
+TEST(AdvertSignature, RejectsPayloadShorterThanHeader) {
+  uint8_t payload[AdvertSignature::kHeaderLen - 1] = {};
+  uint8_t message[AdvertSignature::kMaxMessageLen];
+  const uint8_t* sig = nullptr;
+  EXPECT_EQ(-1, AdvertSignature::buildMessage(payload, sizeof(payload), message, &sig));
+  EXPECT_EQ(-1, AdvertSignature::buildMessage(nullptr, 0, message, &sig));
+}
+
+TEST(AdvertSignature, HeaderOnlyPayloadSignsPubKeyAndTimestamp) {
+  uint8_t payload[AdvertSignature::kHeaderLen];
+  for (int i = 0; i < AdvertSignature::kHeaderLen; i++) payload[i] = static_cast<uint8_t>(i);
+  uint8_t message[AdvertSignature::kMaxMessageLen];
+  const uint8_t* sig = nullptr;
+  EXPECT_EQ(PUB_KEY_SIZE + 4,
+            AdvertSignature::buildMessage(payload, sizeof(payload), message, &sig));
+}
+
+// Oversized unsigned tails must not bypass the observer's opt-in filter.
+TEST(AdvertSignature, RejectsOversizedAppDataLikeHardenedMesh) {
+  uint8_t payload[AdvertSignature::kHeaderLen + MAX_ADVERT_DATA_SIZE + 10];
+  for (size_t i = 0; i < sizeof(payload); i++) payload[i] = static_cast<uint8_t>(i);
+  uint8_t message[AdvertSignature::kMaxMessageLen];
+  const uint8_t* sig = nullptr;
+
+  int len = AdvertSignature::buildMessage(payload, sizeof(payload), message, &sig);
+
+  ASSERT_EQ(-1, len);
+  EXPECT_EQ(nullptr, sig);
+}
+
+TEST(AdvertSignature, ChecksOutputArgumentsAndClearsStaleSignature) {
+  uint8_t payload[AdvertSignature::kHeaderLen + MAX_ADVERT_DATA_SIZE] = {};
+  uint8_t message[AdvertSignature::kMaxMessageLen];
+  const uint8_t* sig = payload;
+  EXPECT_EQ(-1, AdvertSignature::buildMessage(payload, -1, message, &sig));
+  EXPECT_EQ(nullptr, sig);
+  EXPECT_EQ(-1, AdvertSignature::buildMessage(payload, sizeof(payload), nullptr, &sig));
+  EXPECT_EQ(nullptr, sig);
+  EXPECT_EQ(-1, AdvertSignature::buildMessage(payload, sizeof(payload), message, nullptr));
+  EXPECT_EQ(AdvertSignature::kMaxMessageLen,
+            AdvertSignature::buildMessage(payload, sizeof(payload), message, &sig));
+}
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/test/test_companion_mqtt_config.py b/test/test_companion_mqtt_config.py
index e488870f3..50e0e6a78 100644
--- a/test/test_companion_mqtt_config.py
+++ b/test/test_companion_mqtt_config.py
@@ -22,6 +22,7 @@ def function(source, signature):
 
 PREAMBLE = r"""
 #include <cassert>
+#include <initializer_list>
 #include <cctype>
 #include <cstring>
 #include <helpers/CompanionMqttPrefsNvs.h>
@@ -47,20 +48,33 @@ void applyMQTTDefaults(MQTTPrefs* p) {
   memset(p, 0, sizeof(*p));
   for (auto& preset : p->mqtt_slot_preset) strcpy(preset, "none");
 }
-MQTTPrefs saved;
+CompanionMqttPrefsNvs::Record persisted;
+MQTTPrefs& saved = persisted.prefs;
+size_t saved_length = CompanionMqttPrefsNvs::kWriteSize;
 struct Preferences {
   bool begin(const char*, bool) { return true; }
   bool isKey(const char*) { return true; }
   uint16_t getUShort(const char*, uint16_t) { return MQTT_PREFS_VERSION; }
-  size_t getBytesLength(const char*) { return CompanionMqttPrefsNvs::kWriteSize; }
+  size_t getBytesLength(const char*) { return saved_length; }
   size_t getBytes(const char*, void* dest, size_t length) {
-    memcpy(dest, &saved, length);
+    memcpy(dest, &persisted, length);
     return length;
   }
+  size_t putBytes(const char*, const void* source, size_t length) {
+    memset(&persisted, 0, sizeof(persisted));
+    memcpy(&persisted, source, length);
+    saved_length = length;
+    return length;
+  }
+  size_t putUShort(const char*, uint16_t version) {
+    assert(version == MQTT_PREFS_VERSION);
+    return sizeof(version);
+  }
   void end() {}
 };
 struct CompanionMqttSetupPortal {
   static bool loadStoredConfig(MQTTPrefs&);
+  static bool saveStoredConfig(const MQTTPrefs&);
   static bool hasConfiguredSlot(const MQTTPrefs&);
 };
 """
@@ -76,6 +90,35 @@ int main() {
   assert(memcmp(&result, &saved, sizeof(saved)) == 0);
   assert(!CompanionMqttSetupPortal::hasConfiguredSlot(result));
 
+  // Enabling verification persists the appended flag, without lengthening
+  // ordinary default-off Companion records or losing any broker credentials.
+  MQTTPrefs enabled = result;
+  enabled.mqtt_advert_verify = 1;
+  assert(CompanionMqttSetupPortal::saveStoredConfig(enabled));
+  assert(saved_length == 2881);
+  assert(CompanionMqttSetupPortal::loadStoredConfig(result));
+  assert(result.mqtt_advert_verify == 1);
+  assert(strcmp(result.mqtt_slot_password[0], "keep-this-secret") == 0);
+  // Every old recovery padding value is unconditionally default-off.
+  saved_length=2880;
+  for (uint8_t padding : {uint8_t(0), uint8_t(1), uint8_t(255)}) {
+    saved.mqtt_advert_verify=padding;
+    assert(CompanionMqttSetupPortal::loadStoredConfig(result));
+    assert(result.mqtt_advert_verify==0);
+    assert(strcmp(result.mqtt_slot_password[0], "keep-this-secret")==0);
+  }
+  saved_length=2881;
+  saved.mqtt_advert_verify=1; persisted.marker=0; // malformed marker
+  assert(CompanionMqttSetupPortal::loadStoredConfig(result));
+  assert(result.mqtt_advert_verify==0);
+  persisted.marker=CompanionMqttPrefsNvs::kVerifiedMarker;
+  saved.mqtt_advert_verify=255;
+  assert(CompanionMqttSetupPortal::loadStoredConfig(result));
+  assert(result.mqtt_advert_verify == 0);
+  assert(strcmp(result.mqtt_slot_password[0], "keep-this-secret") == 0);
+  assert(CompanionMqttSetupPortal::saveStoredConfig(result));
+  assert(saved_length == 2876);
+
   // Saving a custom broker in stages must not reset it on the next boot.
   strcpy(saved.mqtt_slot_preset[0], "custom");
   assert(CompanionMqttSetupPortal::loadStoredConfig(result));
@@ -143,6 +186,7 @@ class CompanionMqttConfigTests(unittest.TestCase):
         for signature in (
             "static bool isThreeLetterCode",
             "bool CompanionMqttSetupPortal::loadStoredConfig",
+            "bool CompanionMqttSetupPortal::saveStoredConfig",
             "bool CompanionMqttSetupPortal::hasConfiguredSlot",
         ):
             actual += function(source, signature)
diff --git a/test/test_mqtt_advert_verify.py b/test/test_mqtt_advert_verify.py
new file mode 100644
index 000000000..3098f0cb3
--- /dev/null
+++ b/test/test_mqtt_advert_verify.py
@@ -0,0 +1,132 @@
+"""Exercise the production MQTT advert gate and transactional CLI on the host."""
+from pathlib import Path
+import subprocess
+import tempfile
+import unittest
+
+from test_replay_reset_integration import extract_braced
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def compile_run(source):
+    with tempfile.TemporaryDirectory(prefix="mqtt-advert-verify-") as directory:
+        cpp, binary = Path(directory) / "test.cpp", Path(directory) / "test"
+        cpp.write_text(source, encoding="utf-8")
+        result = subprocess.run([
+            "g++", "-std=c++17", "-Wall", "-Wextra", "-Werror", "-Wno-unused-parameter",
+            "-fsanitize=address,undefined", "-fno-sanitize-recover=all",
+            "-fno-pie", "-no-pie", "-I", str(ROOT / "src"),
+            str(cpp), "-o", str(binary),
+        ], text=True, capture_output=True)
+        if result.returncode:
+            raise AssertionError(result.stdout + result.stderr)
+        subprocess.run([str(binary)], check=True)
+
+
+class MqttAdvertVerifyTests(unittest.TestCase):
+    def test_actual_queue_gate_rejects_bad_and_unsigned_tails_only_when_enabled(self):
+        source = (ROOT / "src/helpers/bridges/MQTTBridge.cpp").read_text()
+        method = extract_braced(source, "void MQTTBridge::onPacketReceived(")
+        compile_run(r'''
+#include <cassert>
+#include <initializer_list>
+#include <cstdint>
+#include <cstring>
+#include <helpers/AdvertSignature.h>
+constexpr unsigned PAYLOAD_TYPE_ADVERT=4, PAYLOAD_TYPE_TEXT=2;
+static unsigned verifies=0;
+static bool valid_signature=true;
+namespace mesh {
+struct Packet {
+  uint8_t payload[184] = {};
+  int payload_len=100;
+  unsigned type=PAYLOAD_TYPE_ADVERT;
+  unsigned getPayloadType() const { return type; }
+};
+struct Identity {
+  const uint8_t* pub;
+  explicit Identity(const uint8_t* p) : pub(p) {}
+  bool verify(const uint8_t* sig, const uint8_t* message, int size) {
+    ++verifies;
+    assert(sig == pub+36 && size>=36 && size<=68);
+    assert(!memcmp(pub,message,36));
+    if(size>36) assert(!memcmp(pub+100,message+36,size-36));
+    return valid_signature;
+  }
+};
+}
+struct MQTTBridge {
+  struct Obs { bool mqtt_packets_enabled=true, mqtt_rx_enabled=true, mqtt_advert_verify=false; } obs;
+  Obs* _obs=&obs;
+  bool _initialized=true, type_allowed=true, scope_allowed=true;
+  struct Stop { bool value=false; bool load(int)const{return value;} } _stop_requested;
+  unsigned _filtered_packets=0, _bad_sig_adverts=0, queued=0;
+  bool shouldQueuePacketType(unsigned, bool& filtered) { filtered=!type_allowed; return type_allowed; }
+  bool allowsPacket(mesh::Packet*) { return scope_allowed; }
+  void queuePacket(mesh::Packet*,bool tx){assert(!tx);++queued;}
+  void onPacketReceived(mesh::Packet*);
+};
+namespace std { constexpr int memory_order_acquire=0; }
+''' + method + r'''
+int main() {
+  MQTTBridge bridge; mesh::Packet packet;
+  for(unsigned i=0;i<sizeof(packet.payload);++i) packet.payload[i]=uint8_t(i);
+  // Default off preserves the observer's existing publish-as-heard behavior.
+  valid_signature=false; bridge.onPacketReceived(&packet);
+  assert(bridge.queued==1 && verifies==0 && bridge._bad_sig_adverts==0);
+  bridge.obs.mqtt_advert_verify=true;
+  bridge.onPacketReceived(&packet);
+  assert(bridge.queued==1 && verifies==1 && bridge._bad_sig_adverts==1);
+  valid_signature=true; packet.payload_len=132;
+  bridge.onPacketReceived(&packet);
+  assert(bridge.queued==2 && verifies==2);
+  // Valid signed prefixes cannot bless an appended unsigned byte.
+  for(int size : {99,133,184}) {
+    packet.payload_len=size; bridge.onPacketReceived(&packet);
+    assert(bridge.queued==2 && verifies==2);
+  }
+  assert(bridge._bad_sig_adverts==4);
+  packet.type=PAYLOAD_TYPE_TEXT; bridge.onPacketReceived(&packet);
+  assert(bridge.queued==3 && verifies==2);
+  packet.type=PAYLOAD_TYPE_ADVERT; packet.payload_len=100;
+  bridge.scope_allowed=false; bridge.onPacketReceived(&packet);
+  assert(bridge.queued==3 && verifies==2 && bridge._filtered_packets==1);
+  bridge.scope_allowed=true; bridge.type_allowed=false; bridge.onPacketReceived(&packet);
+  assert(bridge.queued==3 && verifies==2 && bridge._filtered_packets==2);
+}
+''')
+
+    def test_actual_observer_setter_rejects_typos_and_rolls_back_failed_saves(self):
+        source = (ROOT / "src/helpers/CommonCLI_Observer.cpp").read_text()
+        branch = extract_braced(source, 'if (memcmp(config, "mqtt.advert.verify ", 19) == 0)')
+        compile_run(r'''
+#include <cassert>
+#include <cstdint>
+#include <cstring>
+struct CLI {
+  struct { uint8_t mqtt_advert_verify=0; } _mqtt_prefs;
+  bool save_ok=true; unsigned saves=0;
+  bool saveObserverPrefs(){++saves;return save_ok;}
+  bool set(const char* config,char* reply) {
+''' + branch + r'''
+    else return false;
+    return true;
+  }
+};
+int main() {
+  CLI cli; char reply[160]={};
+  assert(cli.set("mqtt.advert.verify on",reply));
+  assert(cli.saves==1 && cli._mqtt_prefs.mqtt_advert_verify==1 && !strcmp(reply,"OK"));
+  assert(cli.set("mqtt.advert.verify onx",reply));
+  assert(cli.saves==1 && cli._mqtt_prefs.mqtt_advert_verify==1 && !strncmp(reply,"Error:",6));
+  cli.save_ok=false; assert(cli.set("mqtt.advert.verify off",reply));
+  assert(cli.saves==2 && cli._mqtt_prefs.mqtt_advert_verify==1 && !strncmp(reply,"Error:",6));
+  cli.save_ok=true; assert(cli.set("mqtt.advert.verify off",reply));
+  assert(cli.saves==3 && cli._mqtt_prefs.mqtt_advert_verify==0 && !strcmp(reply,"OK"));
+}
+''')
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test/test_mqtt_diagnostics.py b/test/test_mqtt_diagnostics.py
index bfcaf823a..fdcd30df7 100644
--- a/test/test_mqtt_diagnostics.py
+++ b/test/test_mqtt_diagnostics.py
@@ -75,6 +75,7 @@ struct MQTTBridge {
   void* _packet_queue_handle = reinterpret_cast<void*>(1);
   int _queue_count = 3, _skipped_publishes = 0;
   unsigned long _filtered_packets = 0;
+  unsigned long _bad_sig_adverts = 0;
   static constexpr int MAX_QUEUE_SIZE = 50;
   bool isSlotReady(int) const { return true; }
   static void formatMqttStatsReply(char*, size_t);
@@ -114,6 +115,10 @@ int main() {
 #endif
   // Normal five-slot stats still fit the fixed LoRa reply budget.
   assert(strstr(reply, "s5=123/4") != nullptr);
+  assert(strstr(reply, "badsig=") == nullptr);
+  bridge._bad_sig_adverts = 7;
+  MQTTBridge::formatMqttStatsReply(reply, sizeof(reply));
+  assert(strstr(reply, "badsig=7") != nullptr);
 
   bridge.logMemoryStatus();
 #ifdef ESP_PLATFORM
@@ -126,6 +131,7 @@ int main() {
   struct { char reply[32]; unsigned char guard[8]; } bounded;
   memset(&bounded, 0xA5, sizeof(bounded));
   bridge._filtered_packets = 4294967295UL;
+  bridge._bad_sig_adverts = 4294967295UL;
   dma_free = 4294967295UL;
   dma_largest = 4294967295UL;
   MQTTBridge::formatMqttStatsReply(bounded.reply, sizeof(bounded.reply));
diff --git a/test/test_mqtt_prefs_codec/test_mqtt_prefs_codec.cpp b/test/test_mqtt_prefs_codec/test_mqtt_prefs_codec.cpp
index 11b25c2fa..70397f345 100644
--- a/test/test_mqtt_prefs_codec/test_mqtt_prefs_codec.cpp
+++ b/test/test_mqtt_prefs_codec/test_mqtt_prefs_codec.cpp
@@ -242,6 +242,7 @@ TEST(MQTTPrefsCodec, CurrentVersionedPayloadRoundTripsExactly) {
   }
   source.display_timeout_secs = 300;
   source.display_flip = 1;
+  source.mqtt_advert_verify = 1;
   std::vector<uint8_t> bytes(Codec::kEncodedSize);
   ASSERT_EQ(Codec::kEncodedSize, Codec::encode(source, bytes.data(), bytes.size()));
 
@@ -331,11 +332,12 @@ TEST(MQTTPrefsCodec, EncodeRefusesAnOutputBufferShorterThanItsChosenPayload) {
   MQTTPrefs longest = defaults();
   longest.mqtt_slot_packet_filter[0] = 0;
   longest.display_flip = 1;
+  longest.mqtt_advert_verify = 1;
   EXPECT_EQ(0u, Codec::encode(longest, bytes.data(), short_size));
   EXPECT_EQ(Codec::kEncodedSize, Codec::encode(longest, bytes.data(), bytes.size()));
 }
 
-TEST(MQTTPrefsCodec, EitherNonDefaultDisplayControlOptsIntoTheFullTail) {
+TEST(MQTTPrefsCodec, EitherNonDefaultDisplayControlKeepsThePreAdvertTail) {
   for (int scenario = 0; scenario < 2; ++scenario) {
     MQTTPrefs source = defaults();
     if (scenario == 0) {
@@ -344,18 +346,70 @@ TEST(MQTTPrefsCodec, EitherNonDefaultDisplayControlOptsIntoTheFullTail) {
       source.display_flip = 1;
     }
 
-    ASSERT_EQ(Codec::kV1BaselinePayloadSize, Codec::payloadLenFor(source));
+    ASSERT_EQ(Codec::kV1PreAdvertPayloadSize, Codec::payloadLenFor(source));
     std::vector<uint8_t> bytes(Codec::kEncodedSize);
-    ASSERT_EQ(Codec::kEncodedSize,
-              Codec::encode(source, bytes.data(), bytes.size()));
+    const size_t written = Codec::encode(source, bytes.data(), bytes.size());
+    ASSERT_EQ(sizeof(MQTTPrefsHeader) + Codec::kV1PreAdvertPayloadSize, written);
+    bytes.resize(written);
 
     const Codec::DecodePlan plan = classify(bytes);
     ASSERT_EQ(Codec::Source::Current, plan.source);
-    ASSERT_EQ(Codec::kV1BaselinePayloadSize, plan.payload_len);
+    ASSERT_EQ(Codec::kV1PreAdvertPayloadSize, plan.payload_len);
     MQTTPrefs loaded = defaults();
     memcpy(&loaded, bytes.data() + sizeof(MQTTPrefsHeader), plan.payload_len);
     EXPECT_EQ(source.display_timeout_secs, loaded.display_timeout_secs);
     EXPECT_EQ(source.display_flip, loaded.display_flip);
+    EXPECT_EQ(0, loaded.mqtt_advert_verify);
+  }
+}
+
+TEST(MQTTPrefsCodec, AdvertVerifyRoundTripsInOneAppendOnlyByteAndDefaultsOffOnOldFiles) {
+  MQTTPrefs source = defaults();
+  strcpy(source.wifi_ssid, "keep-network");
+  strcpy(source.mqtt_slot_password[0], "keep-credentials");
+  EXPECT_EQ(0, source.mqtt_advert_verify);
+  EXPECT_EQ(2864u, Codec::payloadLenFor(source));
+  source.mqtt_advert_verify = 1;
+  EXPECT_EQ(2880u, Codec::payloadLenFor(source));
+  std::vector<uint8_t> bytes(Codec::kEncodedSize);
+  ASSERT_EQ(bytes.size(), Codec::encode(source, bytes.data(), bytes.size()));
+  EXPECT_EQ(1, bytes[sizeof(MQTTPrefsHeader) + 2879]);
+  const Codec::DecodePlan plan = classify(bytes);
+  ASSERT_EQ(2880u, plan.payload_len);
+  MQTTPrefs loaded = defaults();
+  memcpy(&loaded, bytes.data() + sizeof(MQTTPrefsHeader), plan.payload_len);
+  EXPECT_EQ(1, loaded.mqtt_advert_verify);
+  EXPECT_STREQ("keep-network", loaded.wifi_ssid);
+  EXPECT_STREQ("keep-credentials", loaded.mqtt_slot_password[0]);
+
+  // Each shipped older v1 boundary leaves the new default intact.
+  const auto complete = bytes;
+  for (size_t boundary : {size_t(2736), size_t(2860), size_t(2864),
+                           size_t(2876), size_t(2879)}) {
+    bytes = complete;
+    bytes.resize(sizeof(MQTTPrefsHeader) + boundary);
+    writeHeader(&bytes, MQTT_PREFS_VERSION, static_cast<uint16_t>(boundary));
+    const Codec::DecodePlan older = classify(bytes);
+    ASSERT_EQ(Codec::Source::Current, older.source) << boundary;
+    ASSERT_EQ(boundary, older.payload_len);
+    loaded = defaults();
+    memcpy(&loaded, bytes.data() + sizeof(MQTTPrefsHeader), older.payload_len);
+    EXPECT_EQ(0, loaded.mqtt_advert_verify) << boundary;
+    EXPECT_STREQ("keep-network", loaded.wifi_ssid);
+  }
+}
+
+TEST(MQTTPrefsCodec, InvalidAdvertVerifyRepairsWithoutDiscardingCredentials) {
+  MQTTPrefs prefs = defaults();
+  strcpy(prefs.wifi_ssid, "keep-network");
+  prefs.mqtt_advert_verify = 1;
+  EXPECT_FALSE(Codec::repairDisplayPrefs(&prefs));
+  for (uint8_t value : {uint8_t(2), uint8_t(255)}) {
+    prefs.mqtt_advert_verify = value;
+    EXPECT_TRUE(Codec::repairDisplayPrefs(&prefs));
+    EXPECT_EQ(0, prefs.mqtt_advert_verify);
+    EXPECT_EQ(2864u, Codec::payloadLenFor(prefs));
+    EXPECT_STREQ("keep-network", prefs.wifi_ssid);
   }
 }
 
@@ -655,6 +709,12 @@ TEST(MQTTPrefsCodec, LongerDeclaredLengthWithoutTheBytesIsStillCorrupt) {
 }
 
 TEST(CompanionMqttPrefsNvs, WritesRollbackReadableShapeAndAcceptsRecoveryShape) {
+  MQTTPrefs prefs = defaults();
+  EXPECT_EQ(2876u, CompanionMqttPrefsNvs::writeSizeFor(prefs));
+  prefs.mqtt_advert_verify = 1;
+  EXPECT_EQ(2881u, CompanionMqttPrefsNvs::writeSizeFor(prefs));
+  prefs.mqtt_advert_verify = 0;
+  EXPECT_EQ(2876u, CompanionMqttPrefsNvs::writeSizeFor(prefs));
   EXPECT_EQ(MQTT_PREFS_V1_PRE_DISPLAY_PAYLOAD_SIZE,
             CompanionMqttPrefsNvs::kWriteSize);
   EXPECT_LT(CompanionMqttPrefsNvs::kWriteSize, sizeof(MQTTPrefs));
@@ -663,6 +723,8 @@ TEST(CompanionMqttPrefsNvs, WritesRollbackReadableShapeAndAcceptsRecoveryShape)
       MQTT_PREFS_VERSION, CompanionMqttPrefsNvs::kWriteSize));
   EXPECT_TRUE(CompanionMqttPrefsNvs::accepts(
       MQTT_PREFS_VERSION, CompanionMqttPrefsNvs::kRecoverySize));
+  EXPECT_TRUE(CompanionMqttPrefsNvs::accepts(
+      MQTT_PREFS_VERSION, CompanionMqttPrefsNvs::kVerifiedSize));
   EXPECT_EQ(2880u, CompanionMqttPrefsNvs::kRecoverySize);
   EXPECT_LE(CompanionMqttPrefsNvs::kRecoverySize, sizeof(MQTTPrefs));
   EXPECT_FALSE(CompanionMqttPrefsNvs::accepts(
diff --git a/test/test_mqtt_prefs_json_import/test_mqtt_prefs_json_import.cpp b/test/test_mqtt_prefs_json_import/test_mqtt_prefs_json_import.cpp
index d90014067..7492ea04c 100644
--- a/test/test_mqtt_prefs_json_import/test_mqtt_prefs_json_import.cpp
+++ b/test/test_mqtt_prefs_json_import/test_mqtt_prefs_json_import.cpp
@@ -154,7 +154,7 @@ TEST(MQTTPrefsJsonImport, DecodesEveryObserverGroupAndDisplayTail) {
       "wifi:{ssid:\"mesh-net\",password:\"p\\\\\\\"ass\\nword\",power_save:2},"
       "time:{timezone:\"MST7MDT\",utc_offset:-6,ntp_server:\"time.example\"},"
       "mqtt:{origin:\"observer-one\",iata:\"sea\",packets_enabled:1,"
-      "raw_enabled:1,tx_enabled:1,rx_enabled:0,"
+      "raw_enabled:1,tx_enabled:1,rx_enabled:0,advert_verify:1,"
       "status:{enabled:1,interval_ms:60000},"
       "neighbors:{enabled:1,interval_ms:43200000},"
       "owner:{public_key:\"0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\","
@@ -182,6 +182,7 @@ TEST(MQTTPrefsJsonImport, DecodesEveryObserverGroupAndDisplayTail) {
   EXPECT_STREQ("SEA", candidate.mqtt_iata);
   EXPECT_EQ(1, candidate.mqtt_raw_enabled);
   EXPECT_EQ(0, candidate.mqtt_rx_enabled);
+  EXPECT_EQ(1, candidate.mqtt_advert_verify);
   EXPECT_EQ(60000u, candidate.mqtt_status_interval);
   EXPECT_EQ(MQTT_NEIGHBORS_MIN_INTERVAL_MS,
             candidate.mqtt_neighbors_interval);
@@ -213,6 +214,7 @@ TEST(MQTTPrefsJsonImport, MissingFieldsRetainCurrentBuildDefaults) {
   EXPECT_EQ(0, candidate.wifi_power_save);
   EXPECT_EQ(300000u, candidate.mqtt_status_interval);
   EXPECT_EQ(60, candidate.display_timeout_secs);
+  EXPECT_EQ(0, candidate.mqtt_advert_verify);
 }
 
 TEST(MQTTPrefsJsonImport, SemanticRepairsUseSchemaAndCurrentWifiDefaults) {
@@ -221,7 +223,7 @@ TEST(MQTTPrefsJsonImport, SemanticRepairsUseSchemaAndCurrentWifiDefaults) {
   const char* text =
       "{version:1,wifi:{power_save:9},time:{utc_offset:99,ntp_server:\"bad/host\"},"
       "mqtt:{iata:\"bad!\",packets_enabled:-1,raw_enabled:2,tx_enabled:9,"
-      "rx_enabled:2,status:{enabled:3,interval_ms:10},"
+      "rx_enabled:2,advert_verify:5,status:{enabled:3,interval_ms:10},"
       "neighbors:{enabled:2,interval_ms:100},"
       "slot1:{preset:\"bogus\",port:-1,packet_filter:70000}},"
       "snmp:{enabled:2},radio:{watchdog_min:121},"
@@ -238,6 +240,7 @@ TEST(MQTTPrefsJsonImport, SemanticRepairsUseSchemaAndCurrentWifiDefaults) {
   EXPECT_EQ(0, candidate.mqtt_raw_enabled);
   EXPECT_EQ(2, candidate.mqtt_tx_enabled);
   EXPECT_EQ(1, candidate.mqtt_rx_enabled);
+  EXPECT_EQ(0, candidate.mqtt_advert_verify);
   EXPECT_EQ(300000u, candidate.mqtt_status_interval);
   EXPECT_EQ(MQTT_NEIGHBORS_DEFAULT_INTERVAL_MS,
             candidate.mqtt_neighbors_interval);
@@ -267,6 +270,9 @@ TEST(MQTTPrefsJsonImport, RejectsKnownTypeDuplicateLengthAndOverflowErrors) {
            "{version:{x:1}}",
            "{version:1,mqtt:1}",
            "{version:1,mqtt:{slot1:1}}",
+           "{version:1,mqtt:{advert_verify:true}}",
+           "{version:1,mqtt:{advert_verify:\"on\"}}",
+           "{version:1,mqtt:{advert_verify:1,advert_verify:0}}",
            "{version:1,mqtt:{status:{enabled:1},status:{interval_ms:60000}}}"}) {
     MQTTPrefs candidate = defaults;
     EXPECT_FALSE(Import::loaded(decodeText(text, defaults, &candidate))) << text;
@@ -339,16 +345,31 @@ TEST(MQTTPrefsJsonImport, ParsedDisplayPrefsRouteThroughFullAtomicBinaryCommit)
   ASSERT_EQ(Import::Result::Loaded,
             decodeText("{version:1,display:{timeout_s:45,flip:1}}",
                        defaults, &candidate));
-  EXPECT_EQ(MQTT_PREFS_V1_FULL_PAYLOAD_SIZE,
+  EXPECT_EQ(MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE,
             MQTTPrefsCodec::payloadLenFor(candidate));
 
   CommitStore store(true);
   ASSERT_EQ(Atomic::Result::Committed, commitPrefs(&store, candidate));
-  ASSERT_EQ(sizeof(MQTTPrefsHeader) + MQTT_PREFS_V1_FULL_PAYLOAD_SIZE,
+  ASSERT_EQ(sizeof(MQTTPrefsHeader) + MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE,
             store.primary.size());
   MQTTPrefsHeader header = {};
   memcpy(&header, store.primary.data(), sizeof(header));
-  EXPECT_EQ(MQTT_PREFS_V1_FULL_PAYLOAD_SIZE, header.payload_len);
+  EXPECT_EQ(MQTT_PREFS_V1_PRE_ADVERT_PAYLOAD_SIZE, header.payload_len);
+}
+
+TEST(MQTTPrefsJsonImport, AdvertVerifyDefaultsOffRoundTripsAndPersistsThroughBinaryCommit) {
+  const MQTTPrefs defaults = makeDefaults();
+  EXPECT_EQ(0, defaults.mqtt_advert_verify);
+  MQTTPrefs candidate = defaults;
+  ASSERT_EQ(Import::Result::Loaded,
+            decodeText("{version:1,mqtt:{advert_verify:1}}", defaults, &candidate));
+  ASSERT_EQ(1, candidate.mqtt_advert_verify);
+  CommitStore store(true);
+  ASSERT_EQ(Atomic::Result::Committed, commitPrefs(&store, candidate));
+  ASSERT_EQ(sizeof(MQTTPrefsHeader) + 2880u, store.primary.size());
+  MQTTPrefs loaded = defaults;
+  memcpy(&loaded, store.primary.data() + sizeof(MQTTPrefsHeader), 2880);
+  EXPECT_EQ(1, loaded.mqtt_advert_verify);
 }
 
 TEST(MQTTPrefsJsonImport, FailedAtomicPublishPreservesPreviousBinaryImage) {
diff --git a/test/test_transport_filter_wiring.py b/test/test_transport_filter_wiring.py
index 674ccfcc5..fbf11e60a 100644
--- a/test/test_transport_filter_wiring.py
+++ b/test/test_transport_filter_wiring.py
@@ -47,6 +47,10 @@ HARNESS = r'''
 #define MAX_ESPNOW_PACKET_SIZE 256
 unsigned millis() { return 100; }
 namespace mesh {
+struct Identity {
+ explicit Identity(const uint8_t*) {}
+ bool verify(const uint8_t*,const uint8_t*,int) {assert(false);return false;}
+};
 namespace espnow {
  struct ESPNowRawFrames {uint8_t count=0;uint16_t lengths[2]={};uint8_t data[2][256]={};};
  bool encodeEspNowRawFrames(const uint8_t*,size_t,ESPNowRawFrames& f) {f.count=1;return true;}
@@ -57,6 +61,10 @@ namespace bridge {
  const char* espNowFormatName(int) {return "raw";}
 }
 }
+namespace AdvertSignature {
+ constexpr unsigned kMaxMessageLen=68;
+ int buildMessage(const uint8_t*,int,uint8_t*,const uint8_t**) {assert(false);return -1;}
+}
 struct Seen {
  unsigned checks=0,marks=0;
  bool wasSeen(mesh::Packet*) {++checks;return false;}
@@ -112,11 +120,11 @@ struct ESPNowBridge : BridgeBase {
 };
 struct MQTTBridge : BridgeBase {
  std::atomic<bool> _stop_requested{false};
- struct Obs {bool mqtt_packets_enabled=true,mqtt_rx_enabled=true;uint8_t mqtt_tx_enabled=1;} obs;
+ struct Obs {bool mqtt_packets_enabled=true,mqtt_rx_enabled=true,mqtt_advert_verify=false;uint8_t mqtt_tx_enabled=1;} obs;
  Obs* _obs=&obs;
  struct Identity {uint8_t pub_key[32]={};} id;
  Identity* _identity=&id;
- unsigned _filtered_packets=0;
+ unsigned _filtered_packets=0,_bad_sig_adverts=0;
  bool _staged_raw_valid=false;
  bool shouldQueuePacketType(uint8_t,bool&) {return true;}
  void queuePacket(mesh::Packet*,bool) {++queued;}
diff --git a/variants/waveshare_esp32s3_lr1121/platformio.ini b/variants/waveshare_esp32s3_lr1121/platformio.ini
index 8e7b52d4f..f53dad71c 100644
--- a/variants/waveshare_esp32s3_lr1121/platformio.ini
+++ b/variants/waveshare_esp32s3_lr1121/platformio.ini
@@ -100,3 +100,74 @@ lib_deps =
 extends = Waveshare_S3_LR1121
 build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
   +<../examples/kiss_modem/>
+
+[env:Waveshare_S3_LR1121_repeater_observer_mqtt]
+extends = Waveshare_S3_LR1121
+extra_scripts =
+  ${esp32_base.extra_scripts}
+  pre:scripts/generate_cert_bundle.py
+board_ssl_cert_source = adafruit-full
+board_build.embed_files = src/certs/x509_crt_bundle.bin
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D ADVERT_NAME='"MQTT Observer"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D MAX_NEIGHBOURS=50
+  -D WITH_MQTT_BRIDGE=1
+  -D MQTT_MAX_PACKET_SIZE=1024
+  -D MQTT_DEBUG=1
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+  -D CONFIG_MBEDTLS_CERTIFICATE_BUNDLE=y
+  -D ESP32_CPU_FREQ=160
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<helpers/bridges/MQTTBridge.cpp>
+  +<helpers/MQTTMessageBuilder.cpp>
+  +<helpers/JWTHelper.cpp>
+  +<../examples/simple_repeater>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  ${esp32_ota.lib_deps}
+  elims/PsychicMqttClient@^0.2.4
+  bblanchon/ArduinoJson @ 7.4.3
+  arduino-libraries/NTPClient
+  JChristensen/Timezone
+  paulstoffregen/Time@1.6.1
+
+[env:Waveshare_S3_LR1121_room_server_observer_mqtt]
+extends = Waveshare_S3_LR1121
+extra_scripts =
+  ${esp32_base.extra_scripts}
+  pre:scripts/generate_cert_bundle.py
+board_ssl_cert_source = adafruit-full
+board_build.embed_files = src/certs/x509_crt_bundle.bin
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D ADVERT_NAME='"Waveshare LR1121 Room Observer"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D ROOM_PASSWORD='"hello"'
+  -D MAX_NEIGHBOURS=50
+  -D WITH_MQTT_BRIDGE=1
+  -D MQTT_MAX_PACKET_SIZE=1024
+  -D MQTT_DEBUG=1
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+  -D CONFIG_MBEDTLS_CERTIFICATE_BUNDLE=y
+  -D ESP32_CPU_FREQ=160
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<helpers/bridges/MQTTBridge.cpp>
+  +<helpers/MQTTMessageBuilder.cpp>
+  +<helpers/JWTHelper.cpp>
+  +<../examples/simple_room_server>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  ${esp32_ota.lib_deps}
+  elims/PsychicMqttClient@^0.2.4
+  bblanchon/ArduinoJson @ 7.4.3
+  arduino-libraries/NTPClient
+  JChristensen/Timezone
+  paulstoffregen/Time@1.6.1
diff --git a/webui/index.html b/webui/index.html
index 49319f3d3..475245561 100644
--- a/webui/index.html
+++ b/webui/index.html
@@ -492,6 +492,8 @@ body.tab-cli{padding-bottom:0}
         <span class="tgl"><input type="checkbox" data-k="mqtt.raw"><u></u></span></div>
       <div class="sw"><span><b>Received packets</b><i>Report packets heard over the air</i></span>
         <span class="tgl"><input type="checkbox" data-k="mqtt.rx"><u></u></span></div>
+      <div class="sw"><span><b>Drop bad advert signatures</b><i>Skip received adverts that fail verification. Off keeps RF corruption visible to collectors</i></span>
+        <span class="tgl"><input type="checkbox" data-k="mqtt.advert.verify"><u></u></span></div>
       <div class="sw"><span><b>Publish neighbors</b><i>Periodic neighbor table and scopes (PSRAM boards only)</i></span>
         <span class="tgl"><input type="checkbox" data-k="mqtt.neighbors"><u></u></span></div>
       <div class="row" style="margin-top:6px">
@@ -839,6 +841,7 @@ function cfgVal(k){ // map a `set` key to its current value string, from st.cfg
     case"mqtt.origin":return q.origin;case"mqtt.iata":return q.iata;
     case"mqtt.status":return q.status?"on":"off";case"mqtt.packets":return q.packets?"on":"off";
     case"mqtt.raw":return q.raw?"on":"off";case"mqtt.tx":return q.tx;case"mqtt.rx":return q.rx?"on":"off";
+    case"mqtt.advert.verify":return q.advert_verify?"on":"off";
     case"mqtt.interval":return String(q.interval);
     case"mqtt.neighbors":return q.neighbors?"on":"off";case"mqtt.neighbors.interval":return String(q.neighbors_interval);
     case"mqtt.ntp":return q.ntp;
@@ -1960,6 +1963,7 @@ var CLI_KEYS=[
   ["mqtt.packets","Publish packet messages",0,"on|off"],
   ["mqtt.raw","Also publish full raw frames",0,"on|off"],
   ["mqtt.rx","Publish packets heard over the air",0,"on|off"],
+  ["mqtt.advert.verify","Drop received adverts with bad signatures",0,"on|off"],
   ["mqtt.tx","Publish packets this node sends",0,"off|on|advert"],
   ["mqtt.interval","Status publish interval {1-60 min}",0],
   ["mqtt.neighbors","Publish the neighbour table (PSRAM boards)",0,"on|off"],