Opening the socket is kind of difficult. If you have one of the Tri-Wing screwdrivers it is much more easier. If you haven’t got use a normal head screwdriver. Be careful not damaging your hand with it.
Tip: Afterwards use normal cross screws to close the casing.
Connect GPIO0 to GND before connecting power to enable flash mode!
A low pulse on GPIO12 switches the relay on, a low pulse on GPIO5 switches it off.
I have solved the ‘pulse issue’ by setting GPIO12 to always 0 (as LED) and works fine.
More Infos can be found here: #1988.
In the default configuration GPIO0 (which is also used to enable flash-mode) is setup as a Button.
To enable AP-Mode and setup the correct GPIOs as described below,
You can short GPIO0 to GND 4 times as if it was a button (see [[Button-usage]])
Using this method allows you to flash a precompiled binary.
(images from https://github.com/martin-ger/ESP8266-WiFi-Socket)