chore: import upstream snapshot with attribution

docs/en/api-reference/system/bootloader_image_format.rst

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+Bootloader Image Format
+=======================
+
+:link_to_translation:`zh_CN:[中文]`
+
+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:`image-format-bootloader-description` structure.
+
+To get information about the bootloader image, please run the following command:
+
+.. code-block::
+
+    esptool --chip {IDF_TARGET_PATH_NAME} image-info ./build/bootloader/bootloader.bin
+
+The resultant output will resemble the following:
+
+.. code-block::
+
+    esptool v5.0.2
+    Image size: 26352 bytes
+
+    ESP32 Image Header
+    ==================
+    Image version: 1
+    Entry point: 0x40080644
+    Segments: 3
+    Flash size: 2MB
+    Flash freq: 40m
+    Flash mode: DIO
+
+    ESP32 Extended Image Header
+    ===========================
+    WP pin: 0xee (disabled)
+    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 (ESP32)
+    Minimal chip revision: v0.0, (legacy min_rev = 0)
+    Maximal chip revision: v3.99
+
+    Segments Information
+    ====================
+    Segment   Length   Load addr   File offs  Memory types
+    -------  -------  ----------  ----------  ------------
+        0  0x018e8  0x3fff0030  0x00000018  BYTE_ACCESSIBLE, DRAM, DIRAM_DRAM
+        1  0x03e58  0x40078000  0x00001908  CACHE_APP
+        2  0x00f5c  0x40080400  0x00005768  IRAM
+
+    ESP32 Image Footer
+    ==================
+    Checksum: 0x6b (valid)
+    Validation hash: 09fdc81d436a927b5018e19073a787cd37ffce655f505ad92675edd784419034 (valid)
+
+    Bootloader Information
+    ======================
+    Bootloader version: 1
+    ESP-IDF: v6.0-dev-1620-g15d7e41a848-dirt
+    Compile time: Aug  8 2025 16:22:1
+
+
+.. _image-format-bootloader-description:
+
+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
+ * ``secure_version``: the secure version used by the bootloader anti-rollback feature, see :ref:`CONFIG_BOOTLOADER_ANTI_ROLLBACK_ENABLE`.
+ * ``version``: bootloader version, see :ref:`CONFIG_BOOTLOADER_PROJECT_VER`
+ * ``idf_ver``: ESP-IDF version. [#f1]_
+ * ``date`` and ``time``: compile date and time
+ * ``reserved2``: reserved for the future IDF use
+
+.. [#f1] 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