HomeHome AutomationFlashing Tasmota on Sonoff POWR3

Flashing Tasmota on Sonoff POWR3

It takes about 3 min!

In my previous article, I talked about the off the cuff functionality of the Sonoff POWR3. While using it as is, and taking the advantage of the 25A current limit may be the path many will take, I know that a lot of you want to free yourself from the shackles of the eWeLink app (despite having API) and try Tasmota on Sonoff POWR3. Let’s do it.

Tasmota on Sonoff POWR3

Sonoff POWR3 running Tasmota
Sonoff POWR3 running Tasmota

I got everything ready, anticipating the process to be somehow time-consuming, even though I flash so many ESP8266 based devices, that I could do this with my eyes closed. I knew that accessing all needed GPIOs wouldn’t be hard as I poked inside the unit in my previous article. So I got everything ready (just in case):

I wasn’t sure if I could use exposed ETX, ERX pins on the PCB as these were also used to handle power consumption on Sonoff POWR3, but turned out, that I can put my soldering iron away this time, and the process can be completed with female to female dupont wires.

Frankly speaking, it took me about 3 min to complete the process (without the time taken to back up the bin file) thanks to the brilliant tool Tasmotizer. So here is what you need to do:

Mandatory warning: Whatever you do next, it’s on you. I hold no responsibility for your actions! Do not do this with Sonoff POWR3 powered to mains. FTD has enough juice to keep ESP8266 operational.

How to wire FTD programmer and Sonoff POWR3
How to wire FTD programmer and Sonoff POWR3

Open the unit up, you don’t actually have to remove the top-mounted PCB. I have done so to make more space for the camera and in case I need to solder some wires in. Wire the FTD programmer using the following scheme:

FTD ProgrammerSonoff POWR3


One of the buttons on the PCB was kindly marked with “Flashing” indicating where the GPIO00 is. As it’s linked to the toggle button, simply hold the button down when powering on your programmer to put the device into flashing mode.


Unfortunately, the reset button didn’t work for me so I needed to power-cycle the device (by unplugging the FTD programmer) to enter the flash mode and send Tasmota on Sonoff POWR3.

I would strongly suggest you back up the original firmware, but if you live dangerously, go ahead with the process. Flashing lasts about 3 min, and if you never used Tasmotizer, check this article for details.

Power cycle the device once the flash is completed and you can use the Device Config button to configure your WiFi. Now that you have Tasmota on Sonoff POWR3 you can simply access the web interface to finish off the process.

Configuring Tasmota on Sonoff POWR3

To configure Tasmota on Sonoff POWR3, I needed a starting point. I picked the settings for Sonoff POWR2, to see how closely mapping follows the last generation. It turns out, it follows pretty closely. All I had to do is to inverse the setting of the relay and I was good to go.

You can either set the relay to Relay_ior use the configuration template below to set Tasmota on Sonoff POWR3 correctly:

{"NAME":"Sonoff POWR3","GPIO":[32,3072,0,3104,0,0,0,0,256,320,0,0,0,0],"FLAG":0,"BASE":43}

Save the template, set it as active and restart the device. Once powered on, you should have Tasmota on Sonoff POWR3 ready for action.

Final Thoughts

It was much easier and quicker than expected. Thanks to the integrated headers, the process didn’t require soldering and thanks to the abundance of spare GPIOs, you will be able to connect a lot of sensors to Sonoff POWR3. Let me know if you had any issues flashing Tasmota on Sonoff POWR3 in this Reddit thread. I have more Sonoff devices to play with, but I’m not allowed to talk about it just yet. One, in particular, is very cool. Keep in touch to find out!


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