The device has an ESP32-S2 module that allows it to be identified as a keyboard + USB disk. It also a microSD slot that can be identified as MSC SD Card.

The new ESP32-S2 module from Espressif addresses the security flaws in the original ESP32. While the ESP32-S2 does include improved security features, it lacks the BLE capabilities of the original ESP32 module. But it supports native USB.

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WUDopen in new window


  • ESP32-S2 Module
    • Xtensa® Single-Core 32-bit LX7 Microprocessor (up to 240MHz)
      • RISC-V ULP Coprocessor
      • 128KB ROM and 320KB SRAM
      • 4MB of Embedded SPI Flash Storage
    • Cryptographic Hardware Accelerators
      • AES, ECB/CBC/OFB/CFB/CTR, GCM, SHA, RSA, and ECC (Digital Signature)
    • Physical Security Features
      • Transparent external flash and RAM encryption (AES-XTS)
      • Secure Boot feature ensures only signed firmware (with RSA-PSS signature) is booted
      • HMAC and Digital Signature modules use software inaccessible keys to generate SHA-MAC and MAC signatures
    • Integrated 802.11 b/g/n WiFi 2.4GHz Transceiver (up to 150Mbps)
    • Integrated Temperature Sensor (-20°C to 110°C)
    • Operating Voltage: 3.0 to 3.6V
      • WiFi: 310mA (peak)
      • Light-Sleep: 550µA
      • Deep-Sleep: 20-235µA
  • USB-A Connector
  • Micro SD slot
  • Reset and GPIO0 button of ESP32 S2. One of button is hall sensor

Hardware overview

  • Board Dimensions
    • 17mm x 50mm (Without USB case)
    • 19mm x 62mm (With USB case)
  • USB-A Connector
  • Micro SD slot
  • ESP32-S2 mini Module
  • Buttons
    • Reset button
    • GPIO0 for program
  • Status LED - This indicator is connected to GPIO 21

PCB version changes

  • PCB v1.2
    • Reset button - Hall sensor
    • GPIO0 - K1
  • PCB v1.1
    • Reset button - K1
    • GPIO0 - Hall sensor

Device Firmware Upgrade through USB

The ESP32-S2 chip needs to be in bootloader mode for the detection as a DFU device and flashing. This can be achieved by pulling GPIO0 down, pulsing RESET down for a moment and releasing GPIO0.

How to make the ESP32-S2 go to bootloader mode

  1. Plug the WUD to laptop
  2. Pull down and hold the GPIO0 button
  3. Press the reset button, WUD will go to bootloader mode now

See Device Firmware Upgrade via USBopen in new window for more information

Software overview

The pre-flashed firmware is "Wireless USB diskopen in new window". It use ESP32-S2 as an USB Disk with Wireless accessibility. HTTP file server be used with both upload and download capability.

Note: It's a demo code. Don't use it in serious application.



Last Updated:
Contributors: yanc