Esptool
esptool is a popular, open-source Python utility used to flash, provision, and interact with Espressif Systems microcontrollers (like the ESP32 and ESP8266). It communicates directly with the chip's ROM bootloader to upload firmware binaries, read device information, and back up memory.
Getting started is easy:
pip install esptool
You can check if it is working by running:
esptool chip-id
esptool v5.3.0
Connected to ESP32 on COM5:
Chip type: ESP32-D0WD-V3 (revision v3.1)
Features: Wi-Fi, BT, Dual Core + LP Core, 240MHz, Vref calibration in eFuse, Coding Scheme None
Crystal frequency: 40MHz
MAC: f4:2d:c9:71:c6:e4
Stub flasher running.
Warning: ESP32 has no chip ID. Reading MAC address instead.
MAC: f4:2d:c9:71:c6:e4
Hard resetting via RTS pin...
esptool.py --chip esp32 --port /dev/ttyUSB0 read_mac
Then you can use it to flash your ESP32:
esptool.py --chip esp32 --port /dev/ttyUSB0 write_flash -z 0x1000 esp32-20210902-v1.17.0.bin
esptool -h
Usage: esptool [OPTIONS] COMMAND [ARGS]...
esptool v5.3.0 - serial utility for flashing, provisioning, and interacting with Espressif SoCs.
╭─ Options ────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ --chip -c [auto|esp8266|esp32|esp32s2|esp32s3|esp32c3| Target chip type. │
│ esp32c2|esp32c6|esp32c61|esp32c5|esp32e22|es │
│ p32h2|esp32h21|esp32p4|esp32h4|esp32s31] │
│ --port -p SERIAL-PORT Serial port device. │
│ --baud -b BAUD-RATE Serial port baud rate used when │
│ flashing/reading. │
│ --port-filter [TEXT] Serial port device filter, can be vid=NUMBER, │
│ pid=NUMBER, name=SUBSTRING, serial=SUBSTRING. │
│ --before [default-reset|usb-reset|no-reset|no-reset-n Which reset to perform before connecting to │
│ o-sync] the chip. │
│ --after -a [hard-reset|soft-reset|no-reset|no-reset-stu Which reset to perform after operation is │
│ b|watchdog-reset] finished. │
│ --no-stub Disable launching the flasher stub, only talk │
│ to ROM bootloader. Some features will not be │
│ available. │
│ --trace -t Enable trace-level output of esptool │
│ interactions. │
│ --verbose -v Print all output, disable collapsing output │
│ stages. │
│ --silent -s Silence all output except for errors. │
│ --override-vddsdio [1.8V|1.9V|OFF] Override ESP32 VDDSDIO internal voltage │
│ regulator (use with care). │
│ --connect-attempts INTEGER Number of attempts to connect, negative or 0 │
│ for infinite. Default: 7. │
│ --help -h Show this message and exit. │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
╭─ Basic commands ─────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ write-flash Write a binary blob to flash. The address is followed by binary filename, separated by │
│ space. │
│ read-flash Read SPI flash memory content. │
│ erase-flash Erase the SPI flash memory. │
│ erase-region Erase a region of the SPI flash memory. │
│ read-mac Print the device MAC address. │
│ flash-id Print the SPI flash memory manufacturer and device ID. │
│ elf2image Create an application image from ELF file │
│ image-info Print information about a firmware image (bootloader or application). │
│ merge-bin Merge multiple raw binary files into a single flashable file. │
│ version Print esptool version. │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
╭─ Advanced commands ──────────────────────────────────────────────────────────────────────────────────────────────────╮
│ verify-flash Verify a binary blob against the flash memory content. │
│ load-ram Download an image to RAM and execute. │
│ dump-mem Dump arbitrary memory to a file. │
│ read-mem Read arbitrary memory location. │
│ write-mem Modify or write to arbitrary memory location. │
│ read-flash-status Read SPI flash memory status register. │
│ write-flash-status Write SPI flash memory status register. │
│ read-flash-sfdp Read SPI flash SFDP (Serial Flash Discoverable Parameters). │
│ get-security-info Print security information report. │
│ chip-id Print the device chip ID. │
│ run Run application code loaded in flash. │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯