Slave I

Slave I is a specialized firmware project designed for the M5Stack Tab5, serving as a comprehensive wireless research and education toolkit. The project is engineered to leverage the unique dual-MCU capabilities of the ESP32-P4 and ESP32-C6 platform, providing researchers with a powerful handheld device for protocol analysis and security auditing.

Dual-Chip Architecture

The technical foundation of Slave I is its sophisticated split-processing architecture. The system orchestrates tasks between two distinct Espressif microcontrollers:

• ESP32-P4: Serves as the primary application processor, managing the high-resolution LVGL user interface, file system operations, and overall logic orchestration.
• ESP32-C6: Functions as the dedicated radio engine, executing low-level wireless tasks across Wi-Fi, Bluetooth Low Energy (BLE), and 802.15.4 (Zigbee/Thread) protocols.

These chips communicate via an RPC protocol over an esp_hosted SDIO link. This design ensures that the user interface remains responsive even during high-bandwidth radio operations or intensive signal processing tasks.

Wireless Protocol Analysis

Slave I provides a suite of tools for interacting with and analyzing various wireless environments. Its capabilities include:

• Wi-Fi Research: Supports scanning across both 2.4 GHz and 5 GHz bands, handshake and EAPOL capture to .pcap format, and the deployment of captive portal templates for security testing.
• BLE Discovery: Features a scanner with vendor resolution, utilizing a built-in company-ID and OUI database to identify nearby Bluetooth devices.
• 802.15.4 / Zigbee: Includes an energy scanner and device sniffer capable of identifying PAN IDs, EUI-64 addresses, and frame types. It supports raw frame capture for analysis in external tools like Wireshark.
• Unified Radar: A “Nearby” mode provides a real-time visualization of the local wireless spectrum, sorting Wi-Fi and BLE signals by signal strength (RSSI).

User Interface and Development

The firmware features a touch-optimized UI built with the LVGL graphics library, supporting themes and live KPIs. Beyond the touch interface, Slave I is designed for field use with support for physical keyboard navigation via I2C or USB HID.

For developers, the project includes a desktop emulator that uses SDL2 to render the UI on a standard PC. This allows for rapid iteration of the interface and domain logic without requiring physical hardware for every build. The firmware is built using the ESP-IDF 5.4.2 framework, leveraging FreeRTOS for task management and the NimBLE stack for Bluetooth connectivity. It also incorporates a robust file management system for handling captures and logs on a microSD card.