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

Example Output

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I (4601) simple_ota_example: Starting OTA example task
I (4611) simple_ota_example: Attempting to download update from https://192.168.4.102:8070/simple_ota.bin.xz.packed
I (4621) main_task: Returned from app_main()
I (5071) esp_https_ota: Starting OTA...
I (5071) custom_image: OTA to ota_1
I (5071) esp_https_ota: Writing to partition subtype 17 at offset 0x150000
I (13131) simple_ota_example: OTA Succeed, Rebooting...
...
I (115) boot_custom: bootloader plus version: 0.2.6
I (252) boot_custom: start OTA to slot 0
I (10268) boot_custom: OTA success, boot from slot 0
I (10268) esp_image: segment 0: paddr=00020020 vaddr=3c0c0020 size=2a8cch (174284) map
I (10299) esp_image: segment 1: paddr=0004a8f4 vaddr=3fc92e00 size=02d88h ( 11656) load
I (10301) esp_image: segment 2: paddr=0004d684 vaddr=40380000 size=02994h ( 10644) load
I (10307) esp_image: segment 3: paddr=00050020 vaddr=42000020 size=b1408h (726024) map
I (10427) esp_image: segment 4: paddr=00101430 vaddr=40382994 size=102b0h ( 66224) load
I (10445) boot: Loaded app from partition at offset 0x20000