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ESP32: How to dump configuration header of bootloader.bin

You can use the esptool image_info command to dump the content of the bootloader.bin header.

Make sure to select the right bootloader.bin file and the right --chip.

esptool.py --chip esp32s2 image_info build/bootloader/bootloader.bin

Example output

This example is for a ESP-IDF project running on the ESP32-S2

Image size: 22016 bytes

ESP32S2 Image Header
====================
Image version: 1
Entry point: 0x4004a1c4
Segments: 3
Flash size: 4MB
Flash freq: 80m
Flash mode: DIO

ESP32S2 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: 2 (ESP32-S2)
Minimal chip revision: v0.0, (legacy min_rev = 0)
Maximal chip revision: v1.99

Segments Information
====================
Segment   Length   Load addr   File offs  Memory types
-------  -------  ----------  ----------  ------------
      0  0x016a4  0x3ffe5110  0x00000018  BYTE_ACCESSIBLE, MEM_INTERNAL, DRAM
      1  0x00b18  0x4004a000  0x000016c4  MEM_INTERNAL, IRAM
      2  0x033e4  0x4004e000  0x000021e4  MEM_INTERNAL, IRAM

ESP32S2 Image Footer
====================
Checksum: 0xb7 (valid)
Validation hash: 462e9d9360f06ea4f255b03e47f2f9b6cc5501c23bd3dfd3a73597d61ec55f7c (valid)

Bootloader Information
======================
Bootloader version: 1
ESP-IDF: v5.5-dirty
Compile time: Aug  9 2025 01:00:23