Exploring the nanoFramework Flasher Tool (nanoff) for ESP32 Development

Exploring the nanoFramework Flasher Tool (nanoff) for ESP32 Development


For enthusiasts and professionals diving into IoT development with ESP32, the nanoFramework offers a great platform, especially for those familiar with C#.

A crucial aspect of working with the nanoFramework on ESP32 is using the nanoFramework Flasher Tool, known as ‘nanoff’.

This command-line utility is instrumental in flashing the nanoFramework firmware onto ESP32.

This blog post is a detailed guide on effectively using nanoff for ESP32, ensuring a smooth start to your IoT projects.

The Role of nanoff in IoT Development

nanoff simplifies the process of preparing and maintaining the ESP32 for development with the nanoFramework. It handles tasks like flashing firmware, updating to the latest versions, and configuring network settings, all from the command line.

Getting Started with nanoff


Before using nanoff, ensure the following setup:

  1. ESP32 Development Board: Any standard ESP32 board.
  2. A Windows, Linux, or macOS Computer: With command-line access.
  3. .NET 5.0 SDK or newer: Required to run the nanoff tool. Download it from Microsoft’s official .NET download page.

Installation of nanoff

  • Open a command prompt or terminal.
  • Install nanoff globally using the .NET CLI
  • This command makes the nanoff tool accessible from any command prompt or terminal window.
dotnet tool install -g nanoff

Using nanoff with ESP32

Step 1: Connect Your ESP32

  • Use a USB cable to connect the ESP32 board to your computer.
  • Identify the COM port assigned to the ESP32 board (in Windows, you can find this in the Device Manager under “Ports”).

Step 2: Flashing the Firmware

  • To flash the nanoFramework firmware onto the ESP32, use the following command
  • Replace ESP32_WROOM_32 with the specific model of your ESP32 board, and COMx with the correct COM port.
  • This command downloads the latest nanoFramework firmware for the specified target and flashes it onto the ESP32.
nanoff --target ESP32_WROOM_32 --update --serialport COMx

Step 3: Updating the Firmware

  • Regular firmware updates are crucial for performance and security. To update your ESP32’s firmware, rerun the flashing command:
nanoff --target ESP32_WROOM_32 --update --serialport COMx

Step 4: Network Configuration (Optional)

  • nanoff also facilitates network configuration for your ESP32 board. To configure Wi-Fi settings:
nanoff --target ESP32_WROOM_32 --update --serialport COMx --config --ssid YourWiFiSSID --password YourWiFiPassword

Step 5: Verifying the Installation

  • After flashing, reset your ESP32 board.
  • You can then use Visual Studio with the nanoFramework extension to deploy and run a simple C# program, confirming the successful installation. See Running C# on an ESP32 Microcontroller.

Advanced Usage and Best Practices

  • Custom Firmware: nanoff allows you to flash custom or specific versions of the firmware using the --image parameter.
  • Troubleshooting: If the flashing process fails, check your USB connection, ensure the correct COM port is selected, and try again.
  • Device Compatibility: Before starting, ensure your ESP32 board model is compatible with the nanoFramework.
  • Stay Updated: Regularly check for updates to the nanoFramework and nanoff tool to benefit from the latest features and bug fixes.
  • Command-Line Familiarity: Comfort with command-line operations is beneficial when using nanoff, as it is primarily a CLI tool.


The nanoFramework Flasher Tool, nanoff, is an invaluable asset for developers working with the ESP32 in the .NET ecosystem.

It streamlines the firmware management process, making it easier to start IoT development using C# and the nanoFramework.

By following the guidelines outlined in this post, you can prepare your ESP32 for an array of innovative IoT projects, leveraging the power and convenience of high-level programming in embedded systems development.


Hi, my name is Stephen Finchett. I have been a software engineer for over 30 years and worked on complex, business critical, multi-user systems for all of my career. For the last 15 years, I have been concentrating on web based solutions using the Microsoft Stack including ASP.Net, C#, TypeScript, SQL Server and running everything at scale within Kubernetes.