ESP32 Lifecycle Manager (LCM)

ESP32 Lifecycle Manager (LCM) is a lightweight helper firmware that shepherds an ESP32-based device through its entire lifecycle. You can think of it as the "operations center" that boots first, prepares network access, installs your application firmware, keeps it up to date, and offers recovery tools when something goes wrong. Even if you are new to ESP-IDF, LCM guides you from an unconfigured module to a fully managed device in a few straightforward steps.

How LCM operates

At every boot LCM starts before your application. It evaluates whether the system can continue normal operation or whether maintenance is required. The firmware stores Wi-Fi credentials, checks for new releases, validates firmware signatures, and triggers recovery flows when necessary. This means you do not need to build these management utilities yourself—LCM bundles the essentials for remote lifecycle control of ESP32 devices.

Core capabilities

Access Point (AP) mode

LCM can launch a temporary access point so the device remains reachable even before any Wi-Fi network has been configured. Connect to this hotspot to perform initial setup.

Captive portal (CNA)

When you join the LCM access point a captive portal automatically opens. From this portal you can:

• Select a visible Wi-Fi network and provide its password.
• Add a hidden Wi-Fi network manually by entering the SSID and password.
• Configure the GitHub repository URL where LCM should look for new firmware releases (main.bin and main.bin.sig).
• Blink the status LED for identification so you can confirm you are working with the correct device during installation or servicing.

Downloading and installing main.bin

After provisioning, LCM downloads main.bin and the accompanying main.bin.sig. It validates the SHA-384 signature as well as the reported file size and only activates the firmware when the verification succeeds.

Software update (ota_trigger)

You can initiate an over-the-air update through an OTA trigger (for example via an HTTP request) whenever a new release becomes available.

Hardware-assisted update

LCM can listen to hardware controls such as a physical button to start or confirm the update flow. This is useful for devices that must update without a connected computer.

Reset and recovery options

• Software factory reset – Use the LCM API to erase the stored configuration and reboot the device.
• Hardware factory reset – Quickly power-cycle or reset the device 10 times in succession. Once LCM detects the pattern it starts an ~11 second countdown and performs the factory reset automatically.

Automatic firmware version stamping

During installation or update LCM writes the value of LIFECYCLE_DEFAULT_FW_VERSION so you can verify remotely which firmware version is running.

Typical installation flow

1. First boot – LCM starts in AP mode and exposes the captive portal.
2. Network provisioning – The installer links the device to a Wi-Fi network and stores the GitHub repository that hosts signed firmware releases.
3. Firmware acquisition – LCM downloads main.bin and main.bin.sig, validates both files, and activates the firmware upon success.
4. Normal operation – Your application firmware now runs while LCM remains on standby to handle OTA updates and recovery tasks.

Building LCM with ESP-IDF

1. Install ESP-IDF by following the official Espressif documentation.

2. Select the correct target for your board:

   idf.py set-target esp32        # or esp32s2, esp32s3, esp32c3, ...

3. Build the lifecycle manager firmware:

   idf.py build

   The resulting main.bin will be placed inside the build/ directory.

Signing main.bin

Every firmware release must be accompanied by a signature file. From the project root run:

openssl sha384 -binary -out build/main.bin.sig build/main.bin
printf "%08x" "$(wc -c < build/main.bin)" | xxd -r -p >> build/main.bin.sig

Tip: the repository includes ./generate_sig.sh to automate these commands.

Upload both files to a GitHub release (for example version 0.0.1). Follow Semantic Versioning when deciding on the version number:

• Increase MAJOR for incompatible API changes.
• Increase MINOR when you add backward-compatible functionality.
• Increase PATCH for backward-compatible bug fixes.

Flash instructions by chipset

Use esptool.py (installable via pip install esptool) and replace the filenames with the artifacts produced by your build.

ESP32

python -m esptool --chip esp32 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 40m \
  0x1000 esp32-bootloader.bin \
  0x8000 esp32-partition-table.bin \
  0xe000 esp32-ota_data_initial.bin \
  0x20000 esp32-lifecycle-manager.bin

ESP32-S2

python -m esptool --chip esp32s2 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m \
  0x1000 esp32s2-bootloader.bin \
  0x8000 esp32s2-partition-table.bin \
  0xe000 esp32s2-ota_data_initial.bin \
  0x20000 esp32s2-lifecycle-manager.bin

ESP32-S3

python -m esptool --chip esp32s3 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m \
  0x0    esp32s3-bootloader.bin \
  0x8000 esp32s3-partition-table.bin \
  0xe000 esp32s3-ota_data_initial.bin \
  0x20000 esp32s3-lifecycle-manager.bin

ESP32-C2

python -m esptool --chip esp32c2 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 60m \
  0x0    esp32c2-bootloader.bin \
  0x8000 esp32c2-partition_table/partition-table.bin \
  0xe000 esp32c2-ota_data_initial.bin \
  0x20000 esp32c2-lifecycle-manager.bin

ESP32-C3

python -m esptool --chip esp32c3 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m \
  0x0    esp32c3-bootloader.bin \
  0x8000 esp32c3-partition-table.bin \
  0xe000 esp32c3-ota_data_initial.bin \
  0x20000 esp32c3-lifecycle-manager.bin

ESP32-C5

python -m esptool --chip esp32c5 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m \
  0x2000 esp32c5-bootloader.bin \
  0x8000 esp32c5-partition-table.bin \
  0xe000 esp32c5-ota_data_initial.bin \
  0x20000 esp32c5-lifecycle-manager.bin

ESP32-C6 / ESP32-C61

python -m esptool --chip esp32c6 -b 460800 --before default_reset --after hard_reset \
  write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m \
  0x0    esp32c6-bootloader.bin \
  0x8000 esp32c6-partition-table.bin \
  0xe000 esp32c6-ota_data_initial.bin \
  0x20000 esp32c6-lifecycle-manager.bin

For ESP32-C61 use the same offsets and swap only the filenames.

Reset and recovery recap

• Software factory reset – Triggered through the LCM API to wipe stored configuration and reboot.
• Hardware factory reset – Power-cycle or reset the device 10 consecutive times. LCM detects the pattern, waits roughly 11 seconds, and then executes the factory reset.

Armed with these steps you can quickly provision an ESP32 device, deploy your own firmware, and keep it managed remotely through LCM.