These jigs allow you to access the serial port of the ESP32C3 inside a UK S60 Sonoff Adapter without breaking the glues and soldering wires to the PCB.

This was reverse engineered from a measured scan of the PCB and adapter open.

DISCLAIMER:

If you do this mod using these 3D printed jigs, you do so AT YOUR OWN RISK, and not mine.  I cannot guarantee the accuracy of your own builds to make this work.

DO NOT EVER PLUG THE S60 INTO A MAINS SOCKET WITH THE JIG FITTED. ALWAYS POWER THE JIG FROM AN EXTERNAL +5V SUPPLY.

YOU WILL BLOW STUFF UP AND INJURE YOURSELF IF YOU PUT 240V AC THROUGH NEUTRAL INTO THIS PROGRAMMER.  YOU WILL ALSO FRY EVERYTHING CONNECTED.

DO NOT EVEN THINK OF DOING IT.

That said, I've done 8 adapters now without any issues.  Other than making the jigs, it takes under a minute to mod an adapter, and longer to flash with new firmware.

The three holes, top to bottom are Rx, Tx, and +5V.  Gnd is obtained from the N (neutral) line of the adapter's plug.  I use a spare UK socket to make connecting neutral/gnd easier on my jig.

The larger drill jig will need to be tapped with a 1.1mm drill bit (ideally using a pinwheel / vice), and the smaller pogo one with a 0.7mm drill bit.

I used 0.7mm x 16mm pogo pins, and partially drilled the small one just to allow the pogos to be mounted.  I then created wire loops and soldered them onto the jig.  This is why the smaller jig has a gap - to allow the Rx, Tx, and +5V wires to come out from under the pogo jig.

The larger jig is use to mark the S60 case in exactly the right place to drill holes.  Using a 1.1mm drill bit and the jig to make three small indents in the plastic.  Remove that jig, and switch to a 0.7mm drill bit - use this in the indents to make the actual holes for your pogo pins.

This is not a project for an inexperienced engineer.  However, if you're familiar with soldering, programming and Arduino nothing should prove too much of a challenge.