Problem

The enum declaration for esp_image_spi_freq_t in components/bootloader_support/include/esp_image_format.h line 40 is missing the typedef keyword.

This causes the compiler to create a global variable instead of a type definition, resulting in "multiple definition" linker errors when building with stricter toolchains (e.g., PlatformIO's xtensa-lx106-elf gcc 10.3.0).

Error Example

ld: libbootloader_support.a(bootloader_init.o):/esp8266-rtos-sdk/components/bootloader_support/include/esp_image_format.h:45: 
    multiple definition of `esp_image_spi_freq_t'

Solution

Add the missing typedef keyword to make it consistent with the enum declaration above it (lines 34-37).

Before

enum {
    ESP_IMAGE_SPI_SPEED_40M,
    ESP_IMAGE_SPI_SPEED_26M,
    ESP_IMAGE_SPI_SPEED_20M,
    ESP_IMAGE_SPI_SPEED_80M = 0xF
} esp_image_spi_freq_t;

After

typedef enum {
    ESP_IMAGE_SPI_SPEED_40M,
    ESP_IMAGE_SPI_SPEED_26M,
    ESP_IMAGE_SPI_SPEED_20M,
    ESP_IMAGE_SPI_SPEED_80M = 0xF
} esp_image_spi_freq_t;

Testing

• Built successfully with PlatformIO xtensa toolchain
• Resolves linker errors
• One-word fix that maintains full backward compatibility