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A minimal firmware for OTA (over the air) flashing Tasmota, HAA, or ESPurna from Mongoose OS or compatible firmware types.


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⚠ Unfortunately, due to missing time, I will no longer be able to maintain this repository or the downloads server. If you are interested, I encourage you to fork the project and continue development. Or, if you are willing (and able) to take over this repo, drop me a message.

Mongoose to Tasmota, Home Accessory Architect or ESPurna

A minimal firmware for OTA (over the air) flashing various target firmwares starting from Mongoose OS.


This is an intermediate firmware that can be used to install Tasmota, Home Accessory Architect, or ESPurna on various Shelly models. It will install the latest stable release of the target firmware.


⚠ This application should generally be safe to use for all supported devices. Still, overwriting a device's boot loader via OTA update is a risky operation. If something unexpected fails, your device may be bricked, unless you know how to flash a new firmware over a wired connection.

ℹ You can go back to Mongoose OS via OTA as well, using this firmware, but be aware that if something fails, your device may be bricked, if you don't know how to flash a new firmware over a wired connection.

Instead of flashing the device manually (see below), you may try the new automagic flashing script. The script requires Python 3 to be installed on your computer. After downloading the script, run python3 -a from the download location. All Shelly devices with stock firmware, which are connected to the same WIFI network, will be found. For each device that is found, you will be asked if you like to convert it.

Use python3 -a -t haa or python3 -a -t espurna to install alternate targets.

⚠ The script is still in an early testing stage, and I would appreciate your feedback. If you want to give feedback, please open an issue.

Before flashing this firmware, connect your device to a WIFI network with internet access. From your browser, open the update URL for your device from the table below. Replace shellyip with the IP address of your Shelly. The device will restart one or two times and attempt to download the traget firmware. If this download succeeds, the device will restart again, and you will see a new WIFI network labeled tasmota-????, HAA-????, or ESPURNA-????. This process should take no longer than 4 - 5 minutes, depending on your network connection.

If you replace mg2tasmota by mg2haa in the update URLs, your device will install the Home Accessory Architect firmware instead of Tasmota. For mg2espurna instead of mg2tasmota, ESPurna Firmware will be installed.

There is a video tutorial on how to flash this firmware. Thank you, digiblur!

If the download fails, or your internet connection is disrupted, simply turn the device off and on again, the intermediate firmware will retry until it succeeds.

In the unlikely event that the WIFI credentials are wrong, the device will try to connect to a backup WIFI with SSID mgos-recover and password RJoPuKC3u5, which you can use for recovery.

Device Update URL Tasmota Template
Shelly 1 http://shellyip/ota?url= {"NAME":"Shelly 1","GPIO":[0,0,0,0,21,82,0,0,0,0,0,0,0],"FLAG":0,"BASE":46}
Shelly 1PM http://shellyip/ota?url= {"NAME":"Shelly 1PM","GPIO":[56,0,0,0,82,134,0,0,0,0,0,21,0],"FLAG":2,"BASE":18}
Shelly Plug S http://shellyip/ota?url= {"NAME":"Shelly Plug S","GPIO":[56,255,158,255,255,134,0,0,131,17,132,21,255],"FLAG":2,"BASE":45}
Shelly 2 http://shellyip/ota?url= {"NAME":"Shelly 2","GPIO":[0,135,0,136,21,22,0,0,9,0,10,137,0],"FLAG":0,"BASE":47}
Shelly 2.5 http://shellyip/ota?url= {"NAME":"Shelly 2.5","GPIO":[56,0,17,0,21,83,0,0,6,82,5,22,156],"FLAG":2,"BASE":18}
Shelly RGBW2 (color mode, latest firmware needed) http://shellyip/ota?url= {"NAME":"Shelly RGBW2","GPIO":[0,0,52,0,40,255,0,0,37,17,39,38,0],"FLAG":0,"BASE":18}
Shelly Dimmer 1 http://shellyip/ota?url= {"NAME":"Shelly Dimmer 1","GPIO":[0,3200,0,3232,5568,5600,0,0,192,0,193,288,0,4736],"FLAG":0,"BASE":18}
Shelly Dimmer 2 http://shellyip/ota?url= {"NAME":"Shelly Dimmer 2","GPIO":[0,3200,0,3232,5568,5600,0,0,193,0,192,0,320,4736],"FLAG":0,"BASE":18}
Shelly EM http://shellyip/ota?url= {"NAME":"Shelly EM","GPIO":[0,0,0,0,0,0,0,0,6,156,5,21,0],"FLAG":15,"BASE":18}
Shelly Bulb http://shellyip/ota?url= not yet available, only flash if you a perfectly certain about what you are doing
Shelly Vintage http://shellyip/ota?url= not yet available, only flash if you a perfectly certain about what you are doing
Shelly Plug US http://shellyip/ota?url= {"NAME":"Shelly Plug US","GPIO":[52,0,57,0,21,134,0,0,131,17,132,157,0],"FLAG":0,"BASE":45}
Shelly Duo http://shellyip/ota?url= {"NAME":"Shelly Duo","GPIO":[0,0,0,0,38,37,0,0,0,0,0,0,0],"FLAG":0,"BASE":18}
Shelly H&T http://shellyip/ota?url= not yet available, only flash if you a perfectly certain about what you are doing
Shelly i3 http://shellyip/ota?url= {"NAME":"Shelly i3","GPIO":[0,0,0,0,0,0,0,0,83,84,82,0,0],"FLAG":2,"BASE":18}
Shelly 1L http://shellyip/ota?url= {"NAME":"Shelly 1L","GPIO":[320,0,0,0,192,224,0,0,0,0,193,0,0,4736],"FLAG":0,"BASE":18}
Shelly Plug 2 http://shellyip/ota?url= not yet available, only flash if you a perfectly certain about what you are doing
Shelly Uni http://shellyip/ota?url= {"NAME":"Shelly Uni","GPIO":[320,0,0,0,225,0,0,0,192,193,0,224,0,4864],"FLAG":0,"BASE":18}
Shelly Duo RGBW http://shellyip/ota?url= not yet available, only flash if you a perfectly certain about what you are doing

For your convenience, the table above also lists the matching Tasmota device templates from which you can use to configure Tasmota after installation.

Home Accessory Architect will boot in setup mode, which is explained in the HAA Wiki.

For ESPurna, the device will boot into the ESPurna base image. You can then either switch to a devices specific version, if your device is supported, or start configuration from the base image.

If device fails to convert, especially the RGBW2, please update to the latest stock firmware and try again.

My device is not listed!

If your device is not listed, please open a new issue so we can try to make it work. Please mention which of the many Shelly firmware files is the right one for your device.

Build the firmware yourself

You can compile a binary version of this firmware using mos tools. Once installed, clone this repository and run mos build --build-var MODEL=Shelly1 --build-var TARGETFW=tasmota --platform esp8266 to create a binary for e.g. a Shelly1 switch located in build/


Thanks to rojer for helping me with the debugging of the initial code.

This firmware is build using a fork of Mongoose OS docker action which can be found here.

The flash-script is a modified version from mongoose-os-apps/shelly-homekit, originally written by andyblac and rojer.


Copyright (C) 2020, Mark Dornbach

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see