1. 在ESP32固件的头部包含了288字节的描述信息。
在ESP32 D:\esp-idf-v4.1\components\bootloader_support\include\esp_app_format.h文件中包含了以下3段头部信息，分别描述了不同的信息，其中第三段描述应用程序的信息。
typedef struct {
uint8_t magic; /*!< Magic word ESP_IMAGE_HEADER_MAGIC */
uint8_t segment_count; /*!< Count of memory segments */
uint8_t spi_mode; /*!< flash read mode (esp_image_spi_mode_t as uint8_t) */
uint8_t spi_speed: 4; /*!< flash frequency (esp_image_spi_freq_t as uint8_t) */
uint8_t spi_size: 4; /*!< flash chip size (esp_image_flash_size_t as uint8_t) */
uint32_t entry_addr; /*!< Entry address */
uint8_t wp_pin; /*!< WP pin when SPI pins set via efuse (read by ROM bootloader,
* the IDF bootloader uses software to configure the WP
* pin and sets this field to 0xEE=disabled) */
uint8_t spi_pin_drv[3]; /*!< Drive settings for the SPI flash pins (read by ROM bootloader) */
esp_chip_id_t chip_id; /*!< Chip identification number */
uint8_t min_chip_rev; /*!< Minimum chip revision supported by image */
uint8_t reserved[8]; /*!< Reserved bytes in additional header space, currently unused */
uint8_t hash_appended; /*!< If 1, a SHA256 digest "simple hash" (of the entire image) is appended after the checksum.
* Included in image length. This digest
* is separate to secure boot and only used for detecting corruption.
* For secure boot signed images, the signature
* is appended after this (and the simple hash is included in the signed data). */
} __attribute__((packed)) esp_image_header_t;
typedef struct {
uint32_t load_addr; /*!< Address of segment */
uint32_t data_len; /*!< Length of data */
} esp_image_segment_header_t;
typedef struct {
uint32_t magic_word; /*!< Magic word ESP_APP_DESC_MAGIC_WORD */
uint32_t secure_version; /*!< Secure version */
uint32_t reserv1[2]; /*!< reserv1 */
char version[32]; /*!< Application version */
char project_name[32]; /*!< Project name */
char time[16]; /*!< Compile time */
char date[16]; /*!< Compile date*/
char idf_ver[32]; /*!< Version IDF */
uint8_t app_elf_sha256[32]; /*!< sha256 of elf file */
uint32_t reserv2[20]; /*!< reserv2 */
} esp_app_desc_t;
上述结构体字段与编译好的bin文件在字节上的对应关系。
