ESP32-S3 dual-role (client + server) fails with `rc=519` on all NimBLE-Arduino versions 2.3.x

[Berg0162]

ESP32-S3 dual-role (client + server) fails with rc=519 on all NimBLE-Arduino versions 2.3.x

Description

When using an ESP32-S3 as both BLE central (client) and BLE peripheral (server), advertising (or connection) fails with:
E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded

• This occurs only on NimBLE-Arduino versions 2.3.x.

• The exact same sketch runs correctly on NimBLE-Arduino version 2.2.3 without changes.

This looks like a regression in how NimBLE configures controller resources (advertising sets, connection pools, or GATT service init) on the ESP32-S3.

---

Minimal Reproduction Code

#include <NimBLEDevice.h>

static bool clientConnected = false;
const NimBLEAdvertisedDevice* foundDevice = nullptr;

// ========== Central (client) callbacks ==========
class clientCallbacks : public NimBLEClientCallbacks {
    void onConnect(NimBLEClient* pClient) {
        Serial.println(">> Client connected");
        clientConnected = true;
    }
    void onDisconnect(NimBLEClient* pClient) {
        Serial.println(">> Client disconnected");
        clientConnected = false;
    }
};

class clientScanCallbacks : public NimBLEScanCallbacks {
    void onResult(const NimBLEAdvertisedDevice* advertisedDevice) {
        Serial.printf(">> Device found: %s\n", advertisedDevice->toString().c_str());
        foundDevice = advertisedDevice;
        NimBLEDevice::getScan()->stop();
    }
};

// ========== Peripheral (server) setup ==========
void setupServer() {
    // Generic Access (0x1800) is implicit, we add DIS and CPS
    NimBLEServer* pServer = NimBLEDevice::createServer();
    // Device Information Service
    NimBLEService* dis = pServer->createService(NimBLEUUID((uint16_t)0x180A));
    NimBLECharacteristic* dis_ManufacturerName = dis->createCharacteristic(NimBLEUUID((uint16_t)0x2A29), \
                                                                                NIMBLE_PROPERTY::READ);
    dis_ManufacturerName->setValue("Vendor");
    dis->start();

    // Cycling Power Service (basic)
    NimBLEService* cps = pServer->createService(NimBLEUUID((uint16_t)0x1818));
    NimBLECharacteristic* cps_Measurement = cps->createCharacteristic(NimBLEUUID((uint16_t)0x2A63), \
                                                        NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::NOTIFY);
    cps_Measurement->setValue("W");
    cps->start();

    Serial.println(">> Server is setup and started!"); 
    pServer->start();

    // Advertising Data setup
    NimBLEAdvertising* pAdvertising = NimBLEDevice::getAdvertising();
    if(pAdvertising->addServiceUUID((uint16_t)0x1818) )
        Serial.println(">> Setting Service [cps] in Advertised data");
    if(pAdvertising->setName("Repro"))
        Serial.println(">> Setting DeviceName in Advertised data");
}

// ========== Main flow ==========
void setup() {
    Serial.begin(115200);
    delay(200);

    Serial.printf("Free heap: %d\n", ESP.getFreeHeap());
    Serial.printf("Free PSRAM: %d\n", ESP.getFreePsram());

    NimBLEDevice::init("Repro");

    setupServer();

    // Client scan setup and start scanning
    NimBLEScan* pScan = NimBLEDevice::getScan();
    pScan->setScanCallbacks(new clientScanCallbacks());
    pScan->setActiveScan(true);
    pScan->start(0, false, false); // NO Restart
    Serial.println(">> Scanning started");
}

void loop() {
    if (foundDevice && !clientConnected) {
        Serial.println(">> Attempting connection...");
        NimBLEClient* client = NimBLEDevice::createClient();
        client->setClientCallbacks(new clientCallbacks(), false);
        if (!client->connect(foundDevice)) {
            Serial.println(">> Connection failed");
        } else {
            Serial.println(">> Connection success");
        }
        foundDevice = nullptr;

        if(NimBLEDevice::startAdvertising()) Serial.println(">> Advertising started!");
        else Serial.println(">> Advertising start FAILED!");

    }

    delay(1000);
}

Steps to Reproduce

1. Flash above sketch on an ESP32-S3 board (tested with LilyGo T-Display S3 and Seeed XIAO S3).

2. Have any connectable BLE device nearby (phone or another ESP32 peripheral).

3. With NimBLE-Arduino version 2.2.3:

   • Device scans, connects, then starts advertising successfully.

4. With NimBLE-Arduino version later than 2.2.3 (from 2.3.0 to present 2.3.4 tested!):

   • Device scans, connects OK.

   • When advertising starts (or on subsequent connection attempt), fails with:

E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded

Expected Behavior

ESP32-S3 should be able to:

• scan & connect as central, then

• advertise as peripheral,
  with at least a small set of services (GA, DIS, CPS).
  This worked fine on NimBLE-Arduino 2.2.3.

Actual Behavior

On NimBLE-Arduino versions 2.3.x:

• Scan + connect still works.

• Advertising (or connection in reversed order) fails with rc=519.

Environment

• Board(s): ESP32-S3 (e.g. LilyGo T-Display S3, Seeed XIAO ESP32S3)

• Arduino-esp32: tested version 3.2.0 until present 3.3.0 (no difference)

• NimBLE-Arduino:

  • ✅ 2.2.3 → works

  • ❌ versions 2.3.x → fail with rc=519

• PSRAM: enabled (8 MB available)

• Heap: ~260 KB free before advertising

Regression Notes

• The issue only appears starting with NimBLE-Arduino versions 2.3.x

• Likely related to how versions later than 2.2.3 configure controller resources (advertising sets, connection pools, or GATT service init) for ESP32-S3.

• Advertising payload size does not affect outcome (tested trimmed down).

• Scanning and advertising are not active simultaneously.

[h2zero]

Try changing this to 24: https://github.com/h2zero/NimBLE-Arduino/blob/5aaade087896d0da77d4e2ff821eaa2a637c3de8/src/nimconfig.h#L141C12-L141C46

[Berg0162]

I have tried the following as you suggested and beyond...

/**
 * @brief Un-comment to change the number of MSYS buffers available.
 * @details MSYS is a system level mbuf registry. For prepare write & prepare \n
 * responses MBUFs are allocated out of msys_1 pool. This may need to be increased if\n
 * you are sending large blocks of data with a low MTU. E.g: 512 bytes with 23 MTU will fail.
 */
#define CONFIG_BT_NIMBLE_MSYS1_BLOCK_COUNT 12

11:22:06.391 -> >> Setting Service [cps] in Advertised data
11:22:06.391 -> >> Setting DeviceName in Advertised data
11:22:06.391 -> >> Scanning started
11:22:06.391 -> >> Device found: Name: , Address: 6d:81:e4:3c:ec:17, manufacturer data:
11:22:06.391 -> >> Attempting connection...
11:22:07.279 -> >> Client connected
11:22:07.279 -> >> Connection success
11:22:07.279 -> E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded
11:22:07.279 -> >> Advertising start FAILED!

#define CONFIG_BT_NIMBLE_MSYS1_BLOCK_COUNT 16

11:25:42.588 -> >> Setting Service [cps] in Advertised data
11:25:42.588 -> >> Setting DeviceName in Advertised data
11:25:42.588 -> >> Scanning started
11:25:42.588 -> >> Device found: Name: , Address: 58:e2:bd:c7:4f:a0
11:25:42.588 -> >> Attempting connection...
11:25:42.756 -> >> Client connected
11:25:42.756 -> >> Connection success
11:25:42.756 -> E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded
11:25:42.756 -> >> Advertising start FAILED!

#define CONFIG_BT_NIMBLE_MSYS1_BLOCK_COUNT 24

11:29:16.318 -> >> Setting DeviceName in Advertised data
11:29:16.318 -> >> Scanning started
11:29:16.318 -> >> Device found: Name: , Address: 6d:81:e4:3c:ec:17, manufacturer data:
11:29:16.318 -> >> Attempting connection...
11:29:17.234 -> >> Client connected
11:29:17.234 -> >> Connection success
11:29:17.234 -> E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded
11:29:17.234 -> >> Advertising start FAILED!

#define CONFIG_BT_NIMBLE_MSYS1_BLOCK_COUNT 32

11:33:23.360 -> >> Setting Service [cps] in Advertised data
11:33:23.360 -> >> Setting DeviceName in Advertised data
11:33:23.360 -> >> Scanning started
11:33:23.360 -> >> Device found: Name: Tacx Neo 24265, Address: d5:23:ff:fe:76:f1,
11:33:23.360 -> >> Attempting connection...
11:33:24.271 -> >> Client connected
11:33:24.271 -> >> Connection success
11:33:24.271 -> E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded
11:33:24.271 -> >> Advertising start FAILED!

#define CONFIG_BT_NIMBLE_MSYS1_BLOCK_COUNT 64

11:36:47.749 -> >> Setting Service [cps] in Advertised data
11:36:47.749 -> >> Setting DeviceName in Advertised data
11:36:47.749 -> >> Scanning started
11:36:47.749 -> >> Device found: Name: , Address: 50:9f:29:34:74:2c, manufacturer data:
11:36:47.749 -> >> Attempting connection...
11:36:48.579 -> >> Client connected
11:36:48.579 -> >> Connection success
11:36:48.579 -> E NimBLEAdvertising: Error enabling advertising; rc=519, Memory Capacity Exceeded
11:36:48.579 -> >> Advertising start FAILED!

[h2zero]

Seems to only be an issue with the S3 as it works fine with original esp32. Not sure what could be causing this.

[Berg0162]

Dear Ryan,
I can confirm that the rc=519 only occurs when using an ESP32S3! It will NOT occur for example with an Adafruit Feather ESP32 V2, that houses an: ESP32 Dual core 240MHz Xtensa® processor with 8MB Flash + 2 MB PSRAM.

[h2zero]

Found the issue, should be resolved in #1018