There are essentially three ways to build your NodeMCU firmware: cloud build service, Docker image, dedicated Linux environment (possibly VM).


Cloud Build Service

NodeMCU "application developers" just need a ready-made firmware. There's a cloud build service with a nice UI and configuration options for them.

Docker Image

Occasional NodeMCU firmware hackers don't need full control over the complete tool chain. They might not want to setup a Linux VM with the build environment. Docker to the rescue. Give Docker NodeMCU build a try.


Take note that you need to clone the repository including Git submodules just as described below for the Linux environment.

Linux Build Environment

NodeMCU firmware developers commit or contribute to the project on GitHub and might want to build their own full fledged build environment with the complete tool chain.

Build environment dependencies, tools and libraries:


sudo apt-get install -y gperf python-pip python-dev flex bison build-essential libssl-dev libffi-dev libncurses5-dev libncursesw5-dev libreadline-dev

Setting up the repository

Run the following command for a new checkout from scratch. This will fetch the nodemcu repo, checkout the dev-esp32 branch and finally pull all submodules:

git clone --branch dev-esp32 --recurse-submodules nodemcu-firmware-esp32

The make command initiates the build process, which will start with the configuration menu to set the build options.


GNU make version 4.0 or higher is required for a successful build. Versions 3.8.2 and below will produce an incomplete firmware image.

Updating your clone from upstream needs an additional command to update the submodules as well:

git pull origin dev-esp32
git submodule init #only if repo was cloned w/o submodules init
git submodule update --recursive

Here is a video walk through by John Lauer (ChiliPeppr) of building the firmware in Linux from scratch with a fresh install of Ubuntu 19 so you can see all of the dependencies needed to get your build completed and flashed to your ESP32 device.

Video walk through for Linux Build Environment

Build Options

All configuration options are accessed from the file sdkconfig. It's advisable to set it up with the interactive make menuconfig - on a fresh checkout you're prompted to run through it by default.

The most notable options are described in the following sections.

Select Modules

Follow the menu path

Component config --->
  NodeMCU modules --->

Tick or untick modules as required.

UART default bit rate

Follow the menu path

Component config --->
  Platform config --->
    UART console default bit rate --->

CPU Frequency

Follow the menu path

Component config --->
  ESP32-specific --->
    CPU frequency --->

Stack Size

If you experience random crashes then increase the stack size and feed back your observation on the project's issues list.

Follow the menu path

Component config --->
  ESP32-specific --->
    Main task stack size --->

Flashing Options

Default settings for flashing the firmware with are also configured with menuconfig:

Serial flasher config --->
  Default serial port
  Default baud rate
  Flash SPI mode --->
  Detect flash size when flashing bootloader --->

Partition Table

IDF's default partition table Single factory app, no OTA does not provide enough room for a firmware including large modules like e.g. http or sodium. To enable full feature sets, NodeMCU uses a custom partition table from components/platform/partitions.csv which allocates ~1.5 MB for the firmware image. During first boot, the firmware creates an additional partition for SPIFFS in the remaining flash space.

For 2MB flash modules an alternative partition table available as components/platform/partitions-2MB.csv. It restricts the SPIFFS partition to ~448 kB and can be used with menuconfig:

Partition Table --->
  Partition Table (Custom partition table CSV)
  (components/platform/partitions-2MB.csv) Custom partition CSV file
  (0x10000) Factory app partition offset