Bootloader Image Format
The bootloader image consists of the same structures as the application image, see Application Image Structures. The only difference is in the Bootloader Description structure.
To get information about the bootloader image, please run the following command:
esptool.py --chip esp32c6 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 esp_bootloader_desc_t
structure which carries specific fields describing the bootloader. This structure is located at a fixed offset = sizeof(esp_image_header_t
) + sizeof(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 CONFIG_BOOTLOADER_PROJECT_VER
idf_ver
- ESP-IDF version.*
date
andtime
- compile date and time.
reserved2
- reserved for the future IDF use.
*
- The maximum length is 32 characters, including null-termination character.
To get the esp_bootloader_desc_t
structure from the running bootloader, use esp_bootloader_get_description()
.
To get the esp_bootloader_desc_t
structure from a running application, use esp_ota_get_bootloader_description()
.
API Reference
Header File
components/esp_bootloader_format/include/esp_bootloader_desc.h
This header file can be included with:
#include "esp_bootloader_desc.h"
This header file is a part of the API provided by the
esp_bootloader_format
component. To declare that your component depends onesp_bootloader_format
, add the following to your CMakeLists.txt:REQUIRES esp_bootloader_format
or
PRIV_REQUIRES esp_bootloader_format
Functions
-
const esp_bootloader_desc_t *esp_bootloader_get_description(void)
Return esp_bootloader_desc structure.
Intended for use by the bootloader.
- 返回
Pointer to esp_bootloader_desc structure.
Structures
-
struct esp_bootloader_desc_t
Bootloader description structure.
Macros
-
ESP_BOOTLOADER_DESC_MAGIC_BYTE
The magic byte for the esp_bootloader_desc structure that is in DRAM.