Skip to content

Latest commit

 

History

History
76 lines (56 loc) · 2.84 KB

bootloader_image_format.rst

File metadata and controls

76 lines (56 loc) · 2.84 KB
Raw

Bootloader Image Format

The bootloader image consists of the same structures as the application image, see :ref:`Application Image Structures <app-image-structures>`. The only difference is in the :ref:`Bootloader Description <image-format-bootloader-description>` structure.

To get information about the bootloader image, please run the following command:

esptool.py --chip {IDF_TARGET_PATH_NAME} image_info build/bootloader/bootloader.bin --version 2

File size: 26576 (bytes)

ESP32 image header
==================
Image version: 1
Entry point: 0x40080658
Segments: 4
Flash size: 2MB
Flash freq: 40m
Flash mode: DIO

ESP32 extended image header
===========================
WP pin: 0xee
Flash pins drive settings: clk_drv: 0x0, q_drv: 0x0, d_drv: 0x0, cs0_drv: 0x0, hd_drv: 0x0, wp_drv: 0x0
Chip ID: 0
Minimal chip revision: v0.0, (legacy min_rev = 0)
Maximal chip revision: v3.99

Segments information
====================
Segment   Length   Load addr   File offs  Memory types
-------  -------  ----------  ----------  ------------
    1  0x01bb0  0x3fff0030  0x00000018  BYTE_ACCESSIBLE, DRAM, DIRAM_DRAM
    2  0x03c90  0x40078000  0x00001bd0  CACHE_APP
    3  0x00004  0x40080400  0x00005868  IRAM
    4  0x00f2c  0x40080404  0x00005874  IRAM

ESP32 image footer
==================
Checksum: 0x65 (valid)
Validation hash: 6f31a7f8512f26f6bce7c3b270f93bf6cf1ee4602c322998ca8ce27433527e92 (valid)

Bootloader information
======================
Bootloader version: 1
ESP-IDF: v5.1-dev-4304-gcb51a3b-dirty
Compile time: Mar 30 2023 19:14:17

Bootloader Description

The DRAM0 segment of the bootloader binary starts with the :cpp:type:`esp_bootloader_desc_t` structure which carries specific fields describing the bootloader. This structure is located at a fixed offset = sizeof(:cpp:type:`esp_image_header_t`) + sizeof(:cpp:type:`esp_image_segment_header_t`).

  • magic_byte - the magic byte for the esp_bootloader_desc structure.
  • reserved - reserved for the future IDF use.
  • version - bootloader version, see :ref:`CONFIG_BOOTLOADER_PROJECT_VER`
  • idf_ver - ESP-IDF version. *
  • date and time - compile date and time.
  • reserved2 - reserved for the future IDF use.

* - The maximum length is 32 characters, including null-termination character.

To get the :cpp:type:`esp_bootloader_desc_t` structure from the running bootloader, use :cpp:func:`esp_bootloader_get_description`.

To get the :cpp:type:`esp_bootloader_desc_t` structure from a running application, use :cpp:func:`esp_ota_get_bootloader_description`.

API Reference

.. include-build-file:: inc/esp_bootloader_desc.inc