meshtastic · jamesarich · Feb 17, 2026 · Feb 17, 2026 · Feb 17, 2026 · Feb 17, 2026
diff --git a/src/BluetoothCommon.cpp b/src/BluetoothCommon.cpp
@@ -11,6 +11,8 @@ const uint8_t FROMRADIO_UUID_16[16u] = {0x02, 0x00, 0x12, 0xac, 0x42, 0x02, 0x78
                                         0xed, 0x11, 0x93, 0x49, 0x9e, 0xe6, 0x55, 0x2c};
 const uint8_t FROMNUM_UUID_16[16u] = {0x53, 0x44, 0xe3, 0x47, 0x75, 0xaa, 0x70, 0xa6,
                                       0x66, 0x4f, 0x00, 0xa8, 0x8c, 0xa1, 0x9d, 0xed};
+const uint8_t FROMRADIOSYNC_UUID_16[16u] = {0x5d, 0x16, 0x69, 0x37, 0x92, 0xc7, 0x63, 0x99,
+                                            0xdb, 0x45, 0x2d, 0x98, 0xc3, 0x50, 0x8a, 0x88};
 const uint8_t LEGACY_LOGRADIO_UUID_16[16u] = {0xe2, 0xf2, 0x1e, 0xbe, 0xc5, 0x15, 0xcf, 0xaa,
                                               0x6b, 0x43, 0xfa, 0x78, 0x38, 0xd2, 0x6f, 0x6c};
 const uint8_t LOGRADIO_UUID_16[16u] = {0x47, 0x95, 0xDF, 0x8C, 0xDE, 0xE9, 0x44, 0x99,

diff --git a/src/BluetoothCommon.h b/src/BluetoothCommon.h
@@ -11,12 +11,14 @@
 #define TORADIO_UUID "f75c76d2-129e-4dad-a1dd-7866124401e7"
 #define FROMRADIO_UUID "2c55e69e-4993-11ed-b878-0242ac120002"
 #define FROMNUM_UUID "ed9da18c-a800-4f66-a670-aa7547e34453"
+#define FROMRADIOSYNC_UUID "888a50c3-982d-45db-9963-c7923769165d"
 #define LEGACY_LOGRADIO_UUID "6c6fd238-78fa-436b-aacf-15c5be1ef2e2"
 #define LOGRADIO_UUID "5a3d6e49-06e6-4423-9944-e9de8cdf9547"
 
 // NRF52 wants these constants as byte arrays
 // Generated here https://yupana-engineering.com/online-uuid-to-c-array-converter - but in REVERSE BYTE ORDER
-extern const uint8_t MESH_SERVICE_UUID_16[], TORADIO_UUID_16[16u], FROMRADIO_UUID_16[], FROMNUM_UUID_16[], LOGRADIO_UUID_16[];
+extern const uint8_t MESH_SERVICE_UUID_16[], TORADIO_UUID_16[16u], FROMRADIO_UUID_16[], FROMNUM_UUID_16[],
+    FROMRADIOSYNC_UUID_16[], LOGRADIO_UUID_16[];
 
 /// Given a level between 0-100, update the BLE attribute
 void updateBatteryLevel(uint8_t level);

diff --git a/src/nimble/NimbleBluetooth.cpp b/src/nimble/NimbleBluetooth.cpp
@@ -45,6 +45,7 @@ constexpr uint16_t kPreferredBleTxTimeUs = (kPreferredBleTxOctets + 14) * 8;
 #define NIMBLE_BLUETOOTH_FROM_PHONE_QUEUE_SIZE 3
 
 NimBLECharacteristic *fromNumCharacteristic;
+NimBLECharacteristic *fromRadioSyncCharacteristic;
 NimBLECharacteristic *BatteryCharacteristic;
 NimBLECharacteristic *logRadioCharacteristic;
 NimBLEServer *bleServer;
@@ -313,6 +314,23 @@ class BluetoothPhoneAPI : public PhoneAPI, public concurrency::OSThread
     {
         PhoneAPI::onNowHasData(fromRadioNum);
 
+        // Check if FromRadioSync is subscribed (indications enabled)
+        // If so, we push a single packet via indication to keep overhead low.
+        if (fromRadioSyncCharacteristic->getSubscribedCount() > 0) {
+            uint8_t fromRadioBytes[meshtastic_FromRadio_size];
+            size_t numBytes = getFromRadio(fromRadioBytes);
+            if (numBytes > 0) {
+                fromRadioSyncCharacteristic->setValue(fromRadioBytes, numBytes);
+#ifdef NIMBLE_TWO
+                fromRadioSyncCharacteristic->indicate(fromRadioBytes, numBytes, BLE_HS_CONN_HANDLE_NONE);
+#else
+                fromRadioSyncCharacteristic->indicate();
+#endif
+            }
+            // If we sent via Sync, we don't notify legacy FromNum to avoid double-processing or confusion.
+            return;
+        }
+
 #ifdef DEBUG_NIMBLE_NOTIFY
 
         int currentNotifyCount = notifyCount.fetch_add(1);
@@ -871,6 +889,8 @@ void NimbleBluetooth::setupService()
         // Allow notifications so phones can stream FromRadio without polling.
         FromRadioCharacteristic = bleService->createCharacteristic(FROMRADIO_UUID, NIMBLE_PROPERTY::READ);
         fromNumCharacteristic = bleService->createCharacteristic(FROMNUM_UUID, NIMBLE_PROPERTY::NOTIFY | NIMBLE_PROPERTY::READ);
+        fromRadioSyncCharacteristic =
+            bleService->createCharacteristic(FROMRADIOSYNC_UUID, NIMBLE_PROPERTY::INDICATE | NIMBLE_PROPERTY::READ);
         logRadioCharacteristic =
             bleService->createCharacteristic(LOGRADIO_UUID, NIMBLE_PROPERTY::NOTIFY | NIMBLE_PROPERTY::READ, 512U);
     } else {
@@ -881,6 +901,9 @@ void NimbleBluetooth::setupService()
         fromNumCharacteristic =
             bleService->createCharacteristic(FROMNUM_UUID, NIMBLE_PROPERTY::NOTIFY | NIMBLE_PROPERTY::READ |
                                                                NIMBLE_PROPERTY::READ_AUTHEN | NIMBLE_PROPERTY::READ_ENC);
+        fromRadioSyncCharacteristic =
+            bleService->createCharacteristic(FROMRADIOSYNC_UUID, NIMBLE_PROPERTY::INDICATE | NIMBLE_PROPERTY::READ |
+                                                                     NIMBLE_PROPERTY::READ_AUTHEN | NIMBLE_PROPERTY::READ_ENC);
         logRadioCharacteristic = bleService->createCharacteristic(
             LOGRADIO_UUID,
             NIMBLE_PROPERTY::NOTIFY | NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::READ_AUTHEN | NIMBLE_PROPERTY::READ_ENC, 512U);

diff --git a/src/platform/nrf52/NRF52Bluetooth.cpp b/src/platform/nrf52/NRF52Bluetooth.cpp
@@ -10,6 +10,7 @@
 #include <utility/bonding.h>
 static BLEService meshBleService = BLEService(BLEUuid(MESH_SERVICE_UUID_16));
 static BLECharacteristic fromNum = BLECharacteristic(BLEUuid(FROMNUM_UUID_16));
+static BLECharacteristic fromRadioSync = BLECharacteristic(BLEUuid(FROMRADIOSYNC_UUID_16));
 static BLECharacteristic fromRadio = BLECharacteristic(BLEUuid(FROMRADIO_UUID_16));
 static BLECharacteristic toRadio = BLECharacteristic(BLEUuid(TORADIO_UUID_16));
 static BLECharacteristic logRadio = BLECharacteristic(BLEUuid(LOGRADIO_UUID_16));
@@ -42,6 +43,14 @@ class BluetoothPhoneAPI : public PhoneAPI
     {
         PhoneAPI::onNowHasData(fromRadioNum);
 
+        if (fromRadioSync.indicateEnabled()) {
+            size_t len = getFromRadio(fromRadioBytes);
+            if (len > 0) {
+                fromRadioSync.indicate(fromRadioBytes, len);
+            }
+            return;
+        }
+
         LOG_INFO("BLE notify fromNum");
         fromNum.notify32(fromRadioNum);
     }
@@ -97,7 +106,7 @@ void onCccd(uint16_t conn_hdl, BLECharacteristic *chr, uint16_t cccd_value)
     // According to the GATT spec: cccd value = 0x0001 means notifications are enabled
     // and cccd value = 0x0002 means indications are enabled
 
-    if (chr->uuid == fromNum.uuid || chr->uuid == logRadio.uuid) {
+    if (chr->uuid == fromNum.uuid || chr->uuid == logRadio.uuid || chr->uuid == fromRadioSync.uuid) {
         auto result = cccd_value == 2 ? chr->indicateEnabled(conn_hdl) : chr->notifyEnabled(conn_hdl);
         if (result) {
             LOG_INFO("Notify/Indicate enabled");
@@ -188,6 +197,12 @@ void setupMeshService(void)
     fromNum.write32(0); // Provide default fromNum of 0
     fromNum.begin();
 
+    fromRadioSync.setProperties(CHR_PROPS_INDICATE | CHR_PROPS_READ);
+    fromRadioSync.setPermission(secMode, SECMODE_NO_ACCESS);
+    fromRadioSync.setMaxLen(sizeof(fromRadioBytes)); // Reuse size
+    fromRadioSync.setCccdWriteCallback(onCccd);
+    fromRadioSync.begin();
+
     fromRadio.setProperties(CHR_PROPS_READ);
     fromRadio.setPermission(secMode, SECMODE_NO_ACCESS);
     fromRadio.setMaxLen(sizeof(fromRadioBytes));