Pull firmware out of ESP

✅ BLUF:

You can extract firmware from the ESP32 using external hardware like a SPI flash reader or by connecting directly to the chip’s SPI flash pins, but it’s often easier and safer to use the UART method unless the flash chip is locked or damaged.

🧰 1. Easiest Method — UART via USB (What You’re Already Doing)

This is using esptool.py over the built-in USB-to-serial converter (or UART pins).

esptool.py --chip esp32 --port /dev/cu.usbserial-120 read_flash 0x000000 0x400000 esp32_firmware.bin

✅ Recommended unless the chip or bootloader is disabled/protected.

🧰 2. Hardware-Based Method — SPI Flash Dump via External Reader

Use this when:

• The ESP32 is damaged or bricked

• UART access is disabled (e.g., for anti-tamper reasons)

• You want to clone an unpowered device

✅ What You Need:

• External SPI flash reader/writer, like:

  • CH341A programmer

  • Bus Pirate

  • FTDI SPI module

• SOIC8 test clip if the flash chip is soldered down

• Flash memory dump software (e.g., flashrom)

🧷 Physical Pinout (typical W25Q32 flash chip):

⚠️ Always confirm with a multimeter and datasheet before wiring.

🔥 Example Using  flashrom with CH341A**

flashrom -p ch341a_spi -r esp32_dump.bin

You may need to run as root (sudo) and disable system SIP protections on macOS.

🧠 Security Note

Most ESP32s do not encrypt flash by default, but if flash encryption is enabled, the dumped binary will be useless without the encryption key stored in eFuses.

🧪 Summary