Supported Targets	ESP32-C2	ESP32-C3

Simple OTA example

Overview

This example demonstrates how to use compressed OTA by the bootloader support plus component.

The basic flow of compressed OTA:

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    ************                        *************
    *bootloader* ---------------------->*   ota_0   *  <-----
    ************                        *************       |
                                                            |decompress
                                        *************       |
                                        *   ota_1   *  ------
                                        *************

Compress the new firmware.
The device to be updated downloads the compressed firmware and restarts.
After restarting, in the bootloader stage, decompress the compressed firmware and write the decompressed data to the specified partition.
Boot the new firmware.

How to use the example

The example is a copy of simple_ota_example. Please refer the README.md for setup details.

You can also use the other samples in esp-idf/examples/system/ota directory to verify compressed OTA.

How to generate compressed firmware

Generate the compressed app firmware in an ESP-IDF "project" directory by running:

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idf.py gen_compressed_ota

This command will compile the project first, then it will generate the compressed app firmware. If there are no errors, the build/custom_ota_binaries directory may contain the following file:

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simple_ota.bin.xz  
simple_ota.bin.xz.packed

The file named simple_ota.bin.xz.packed is the actual compressed app binary file to be transferred.

In addition, if secure boot is enabled, the command will generate the signed compressed app binary file:

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simple_ota.bin.xz.packed.signed

you can also use the script gen_custom_ota.py to compress the specified app:

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python3 gen_custom_ota.py -hv v3 -i simple_ota.bin --add_app_header