Version 3.1

New Features

• Support for ESP32-C3 SoC has been added
• Added --encrypt-files option to specify which files need encryption before flashing.
• Added --use_segments option for elf2image to use segments instead of sections to generate the image. (#546)
• Improved the write_flash timeout calculation and status message.
• Support for detecting ESP8285 versions -N08, -N16, -H08, and -H16 has been added.
• Added support for all write_reg command forms (including delay and mask parameters) to flasher stub.
• Added merge_bin command to combine binary files on host (#254, #568)
• Extended the --min-rev argument of elf2image to work on all chips apart from ESP8266.
• Added diagnostic warnings about the memory regions needing to be erased during a flash write (#306)
• Added --after no_reset_stub option to keep the flasher stub running and allow its repeated usage.
• Added support for the USB-JTAG-Serial peripheral of ESP32-C3.

espsecure.py

• Added custom command-line argument to allow calling from other Python scripts.
• Added --aes-xts option to encrypt/decrypt flash data files with AES-XTS algorithm on the S2 and C3.
• Fixed handling of files to forbid empty output and re-writing input.

espefuse.py

• Added custom command-line argument to allow calling from other Python scripts.
• Added security measures to prevent burning custom multicast MAC address. (#472)
• Fixed errors when burning and read-protecting an efuse at the same time (#584)
• Fixed burning of SPI pins configuration efuses (#216)

Internal features

These features are intended for use inside Espressif:

• Support for ESP32-S3-beta3 & ESP32-C6-beta have been added. These SoCs are not generally available, so they are unsupported in this release. Official support will be added in a later esptool release.
• Support for 32-bit addressing to enable 32/64MB flash memory chips on the S3.

Bug Fixes

• Fixed error outputs when installing from pip.
• Increased the timeout for writing to flash to improve stability (#577, #533)
• Fixed failing dump_mem overall bytes read message.
• Allowed the write_mem mask argument to be optional to match with its usage example on Wiki.
• Ensured expand_file_arguments gets called when using custom command-line arguments. (#400)
• Fixed SecureBoot v2 public key extraction (#623)

Miscellaneous Changes

• Decomposed port detection logic.
• Added flushing after each command before waiting for a reply.
• Made it easier to use esptool.py as a component by permitting passing an already formed esp object to main() (#402)
• Added function to merge adjacent sections in elf2image for the use case of linker scripts that have a large number of sections.
• Decoupled esptool reset logic for easier monkey-patching (#508)

Thanks to @Skallwar, @eykamp, @gnought, @middelink and others for contributing to this release.

Version 3.0

Breaking changes

• The default esptool.py write_flash --flash_size argument has changed from detect to keep. This means that if no --flash_size argument is passed when flashing a bootloader, the value in the bootloader .bin file header is kept instead of detecting the actual flash size and updating the header. To keep the old behaviour, add the argument esptool.py [...] write_flash [...] -fs detect
• espefuse.py command line arguments for ESP32 have changed:
  • BLK1, BLK2, BLK3 is now BLOCK1, BLOCK2, BLOCK3`
  • The key usage secure_boot has been replaced with secure_boot_v1, secure_boot_v2. Secure Boot V2 is the new RSA-based Secure Boot mechanism supported on ESP32 V3.

New Features

• Support for ESP32-S2 SoC has been added
• Support for detecting ESP32-PICO-V3-02 and ESP32-U4WDH have been added
• New --connect-attempts argument (#464)
• Fixed scrolling problems when output is redirected (for example in Arduino IDE, see discussion at #482)
• Produce a meaningful error if the SoC we connect to doesn't match the --chip argument
• Support different capitalization and spelling for --chip argument (ie -c ESP32, -c esp32-s2, etc.
• Added dedicated program esp_rfc_2217_server.py for flashing via RFC2217 (i.e. flashing over the network, #383)

espsecure.py

• Added support for Secure Boot V2 (ESP32 V3, ESP32-S2)
• Secure Boot V1: PKCS8 formatted ECDSA keys are now supported via ecdsa library (not including password protected keys)

espefuse.py

• Added ESP32 ECO3 efuse UART_DOWNLOAD_DIS
• Added new batch burn mode, support burning more than one eFuse on a single command line
• espefuse.py internals have been refactored to support multiple chips, produce more information about which eFuses are being written to which values.
• "Virtual" mode added for host-based testing, allows updating eFuse values on a "virtual" chip inside the host.

Internal features

These features are intended for use inside Espressif:

• Support for ESP32-S3beta2 & ESP32-C3 have been added. These SoCs are not currently available outside Espressif, so these SoCs are unsupported in this release. Official support will be added in a later esptool release.
• esptool.py --no-stub read_flash is now supported on ESP32 and later. This option is slower than using the default stub option to read flash, so it's generally not useful for production SoCs.

Bug Fixes

• Added temporary workaround for a pyserial failure on macOS Big Sur Preview (#540)
• Fixed gcc9 warning in the stub (#501)
• Fixed some memory types printed in the memory map output
• Fixed the check for zero bytes before applying an ELF SHA-256 with elf2image --elf-sha256-offset option (#560)
• Fixed displaying some single core ESP32 features incorrectly, i.e. ESP32-S0WD
• Fixed exception on Python 3 if the same flash address was repeated twice (#558)

Miscellanous Changes

• Updated miniz to v2.1.0 (#500)
• Moved ESP32 stub loader location to facilitate loading large applications direct to IRAM
• Vendored modules ecdsa, pyaes and optional pycrypto have been removed. Pyaes has been replaced with the pyca-cryptography library

Thanks to @jkoelker, @earlephilhower, @paravoid, @niziak, and others for contributing to this release.

Version 2.8

Features

• esptool.py image_info now prints a summary of segment memory types (IRAM, DRAM, etc) based on the address range.
• esptool.py write_flash will warn if it looks like a bootloader binary is built for ESP32-S2 or another newer chip (support for flashing ESP32-S2 will be added in a future version.)

Bug Fixes

• Removed ESP8266 SDK & ESP-IDF dependencies when building the flasher stub binaries. Previously the SDKs were used to include some register address macros, only. This removes any uncertainty about whether the flasher stub binary is a derived work of either SDK. The flasher stub binary itself is the same as the binary in v2.7.
• Fixed minor issues running esptool automated tests on macOS.
• Minor flake8 fixes including compatibility with newer flake8 versions.

ESP32 Only

Features

• Support detection of new ESP32 silicon revisions
• New esptool.py elf2image --min-rev X option allows creating a .bin file which only supports a minimum ESP32 silicon revision.

Bugfixes

• Fix burning custom MAC with espefuse.py when 3/4 Coding Scheme is set (#447)

Version 2.7

Features

• New option write_flash --flash-size keep will keep whatever flash size is set in the bootloader header, matching the behaviour of --flash-mode keep and --flash-speed keep. The default is still --flash-size detect but may be changed to keep in a future major update, to be consistent with the other two options.
• write_flash no longer updates the flash header if the file being written to the bootloader offset isn't a valid image file for the chip. This is useful for flashing pre-encrypted data to ESP32s, where the image file contains ciphertext.
• esptool now always prints the detected crystal frequency (26MHz or 40MHz) as part of general chip information, and will warn if the detected frequency deviates by an unexpected amount.
• Passing arguments to main() from Python is now documented in the README (#408)

Bug Fixes/Changes

• elf2image --sha256-offset will now only write the ELF SHA-256 to this offset if the existing data is all zeroes. Otherwise a warning is printed.
• Improved the error message if esptool searches all serial ports and finds nothing. (#401)

ESP32 Only

Features

• New write_flash --encrypt option that works with the new Development Mode flash encryption that will be the default flash encryption development workflow in ESP-IDF V4.0.
• espefuse.py summary --format json will print a JSON dictionary of efuse summary data (#436)
• espefuse.py burn commands now set the efuse timing before burning, in line with recent ESP32 TRM update.
• espsecure.py key operations now support --keylen argument, allowing 192-bit keys for ESP32s with 3/4 Coding Scheme set.
• espsecure.py encryption and decryption speed substantially improved. (#416)

Bug Fixes/Changes

• FLASH_CRYPT_CNT efuse is now defined as 7 bits wide, as eight bit is not used by flash encryption hardware.

ESP8266 Only

Bug Fixes/Changes

• Flasher stub is now built with gcc 5.2.0 toolchain.

Thanks to @grandcat, @darkfader, @tim-nordell-nimbelink, @sbertrand-witekio, @marcelstoer, @eykamp, @cclauss for contributing to this release.

Version 2.6

Features

• New write_flash --erase-all ... option to erase all flash before writing (single command). (#344)
• Support patching the SHA256 digest of the ELF file into the binary (available in ESP-IDF via app description APIs)
• Make calling esptool module functions and esptool.main() more Python-friendly (all functions clean up open files correctly, main(...) can take an optional argument with a command line formatted as a list.) (#341)

Bug Fixes/Changes

• Fix crash due to unimplemented write timeout on RFC2217 ports
• elf2image no longer adds empty ELF sections (zero length) to the .bin file
• elf2image fails with a proper error if an ELF file contains more than 16 loadable sections
• Improve error message if list_ports is missing from pyserial (#350)
• Fix some write_flash timeouts writing large but highly compressible payloads

ESP8266 Only

• Fix bug where flashing with stub would fail if ESP8266 was in deep sleep immediately beforehand. (#351)

ESP32 Only

Features

• Support for reading/writing efuses when 3/4 Coding Scheme is set details.
• espefuse.py supports displaying and setting a custom MAC address in BLK3 of efuse
• espsecure.py can now verify signatures with raw binary key file as well as PEM formatted key file (#357)

Bug Fixes/Changes

• Workaround a mapping bug in the ESP-IDF bootloader (if IROM/DROM segment ended less than 0x20 bytes after a page boundary, older ESP-IDF bootloaders would not map the final page correctly).
• Reformat espefuse.py summary output (includes: read-only efuses now display value ? not 0, byte order of keys shown for BLK1,BLK2 are now shown in software order not the reversed byte order used by hardware cryptographical modules.)
• espsecure.py: Fix Python 3 compatibility issues (includes #369 #382)

Special thanks to @Callahan93 and @borro0 for contributing to this release.

Version 2.5.1

Bug fixes:

• Errors during chip detection are now formatted correctly.
• OSError is handled correctly while scanning for a port (#322)
• Update link to flashrom repo for SPI flash chip IDs (#338)
• read_flash command: Error out immediately if an invalid length packet is received (common symptom of bad serial link) (#342)

ESP32 Only:

• espefuse.py: Disable burning key efuses when 3/4 Coding Scheme is set (support for burning keys with 3/4 Coding Scheme will be added in a future update).

Thanks to @orangecms for contributing to this release.

Version 2.5.0

New features:

• Set a write timeout in pyserial (prevents hanging in sync process if port is unavailable).
• (ESP32) New option elf2image --secure-pad to pad the output binary so once signed it will align to an flash cache page boundary (64KB). Prevents unsigned data from being mapped into the instruction space via the flash cache.

Bug fixes:

• Fix exception if no --port is specified but no serial ports are found in the system.
• (ESP32) espsecure: Fix bug where digest_secure_bootloader could produce an incorrect digest.

Thanks to @heyinling & @ekiro for contributing to this release.

Version 2.4.1

Bug fixes:

• --port argument was not correctly handled in v2.4.0
• Corrected pyserial dependency to require pyserial v3.0 or newer

Thanks to @nopdotcom and @ildar for contributing to this release.

Version 2.4.0

Version 2.4.0:

ESP8266 & ESP32 changes

• If no serial port is specified, try all serial ports until an Espressif
  device responds.
• Print device MAC on every command, after connecting.
• New option --before no_reset_no_sync for use when immediately reusing the
  serial port with an already-running loader.
• Fix spurious load_ram error when executed code immediately resets the UART
  baud rate..
• Produce an error if load_ram is going to clobber bootloader stub memory (can use
  --no-stub to work around this).
• Display a helpful error if the incompatible 'serial' module was installed
  instead of 'pyserial'.
• Explicitly close the serial port at end of main() function (allows calling
  esptool.main() from another Python program for basic scripting.)
• Workaround Windows usbser.sys (USB CDC-ACM device) driver bug setting DTR & RTS
• Flasher stub build updates to work with recent ESP-IDF & ESP8266 SDK headers
• Flasher stub now sends correct length field in protocol responses (esptool.py
  was ignoring this field, but some other tools were not).

ESP8266 changes

• Move the loader stub to the very end of IRAM (useful when using load_ram command).
• elf2image --version=2 is now compatible with recent ESP8266 SDK bootloader
  and produces the same binary output as ESP8266 SDK gen_app.py.
• Remove unsupported flash size 4MB-c2

ESP32 changes

• Print chip frequency rating values in Features list, for chips where these are
  set.
• Working load_ram command.
• espefuse.py: Support setting the baud rate.
• New --override-vddsdio option allows setting the VDDSDIO regulator to 1.8V,
  1.9V or "OFF" when connecting (to override the default value read from efuse).
  To avoid hardware damage, forcing VDDSDIO to 3.3V is not supported.

Thanks to @devanlai, @andrewwakeling, @Callahan93, @tim-nordell-nimbelink, @cefn
and @nkolban for contributing to this release.

Version 2.3.1

Latest stable release available from PyPi:
https://pypi.python.org/pypi/esptool/

This release:
https://pypi.python.org/pypi/esptool/2.3.1

New since v2.3

• Fixes a bug where Features line was mis-formatted for ESP8266 and triggered an exception on ESP8285.