The Sonoff Touch is a switch device with a built-in Wifi module, capable of being activated remotely.

To program the Sonoff Touch a serial connection is needed - this can be modernly achieved using an USB TTL FTDI converter coupled to the serial interface on the Sonoff Touch board.

The Sonoff Touch serial connectors can be found on the Wifi board with the following wiring:

Furthermore, the Sonoff Touch does not map the GPIO button necessary for setting the device in programming mode to the main switch. Instead, a lead must be attached to the pin marked in the image to be able to set the device in programming mode.

With the wires attached, the USB programmer can be used to upload a firmware such as Tasmota to replace the default firmware.

To flash the firmware, attach all the serial port wires TX, RX, GND and Vcc and then make a connection between the GPIO wire and some grounding whilst inserting the USB cable. One way to ground the GPIO wire is to just touch the USB casing with the wire.

The rest of the flashing procedure is the same for all Sonoff devices.