MicroPython Forum (Archive)

For the upcoming 1.8.6 release, use of the latest esptool 1.2.1 is required:

• If you use esp-open-sdk, you don't need to do anything if you followed last notice of required upgrade http://forum.micropython.org/viewtopic. ... 689#p14850 . However, I'd recommend to rebuild to make sure you didn't miss earlier upgrade and get everyone on the actual 1.2.1, not pre-release.
• Otherwise, if you installed just esptool.py, upgrade using "pip install esptool"
• If you use any other flashing utility, which is not officially supported and you do this on your own risk and under self-support, please be sure to set the exact flash size of your module.

Rationale of the changes: MicroPython previously supported flash size auto-detection on first boot, so you could just use 8mbit size with esptool.py. With ESP8266 SDK2.0 this is no longer possible, auto-detection was moved to esptool.py instead.

Note that auto-detection works only for standard flash sizes supported for ESP8266, i.e. up to 4Mbyte.

Thanks Paul!
The auto-detect PR for those interested.

Esptool.py is now supported by Espressif and lives at https://github.com/espressif/esptool, previously https://github.com/themadinventor/esptool

The auto-detect update is fantastic if you have a few boards. (Like me, I buy all of them )

Argh, I was hoping that the 1.2 relase gets finally python3 support.
Seems, they moved that over to the 1.3 milestone.
Thus, Arch Linux users still have to patch the file to explicitly call python2.

I'm unable to flash my ESP8266 with esptool.py 1.2.1

Following error appears:
> esptool.py --port /dev/tty.SLAB_USBtoUART --baud 460800 write_flash --flash_size=detect -fm dio 0 esp8266-20161110-v1.8.6.bin
esptool.py v1.2.1
Connecting...
Auto-detected Flash size: 32m
Running Cesanta flasher stub...

A fatal error occurred: Invalid head of packet ('\xf8')

I've tried also the latest esptool.py (1.3-dev) and I get a similar fatal error. Flashing a previous version of the firmware also fails. However, erasing flash works with both versions of esptool.py.

Any ideas?

ceres wrote:I'm unable to flash my ESP8266 with esptool.py 1.2.1

Following error appears:
> esptool.py --port /dev/tty.SLAB_USBtoUART --baud 460800 write_flash --flash_size=detect -fm dio 0 esp8266-20161110-v1.8.6.bin

Rather late answer sorry, but did you try a lower serial baud rate? Many people report that baudrates above 115200 fails.

pfalcon wrote:For the upcoming 1.8.6 release, use of the latest esptool 1.2.1 is required:

[*] Otherwise, if you installed just esptool.py, upgrade using "pip install esptool"

I am trying to upgrade my version of esptool per your instructions above so that I may upgrade to 1.8.6 firmware. I get the following messsage from the command prompt in windows:


C:\Python27\Scripts>pip install esptool
Requirement already satisfied (use --upgrade to upgrade): esptool in c:\python27\lib\site-packages
Requirement already satisfied (use --upgrade to upgrade): pyserial in c:\python27\lib\site-packages (from esptool)
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

C:\Python27\Scripts>

weldeng wrote:

pfalcon wrote:For the upcoming 1.8.6 release, use of the latest esptool 1.2.1 is required:

[*] Otherwise, if you installed just esptool.py, upgrade using "pip install esptool"

I am trying to upgrade my version of esptool per your instructions above so that I may upgrade to 1.8.6 firmware. I get the following messsage from the command prompt in windows:


C:\Python27\Scripts>pip install esptool
Requirement already satisfied (use --upgrade to upgrade): esptool in c:\python27\lib\site-packages
Requirement already satisfied (use --upgrade to upgrade): pyserial in c:\python27\lib\site-packages (from esptool)
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

C:\Python27\Scripts>

The following appears to have worked


"pip install esptool==1.2.1"