At the heart of the ESP-01 module is the ESP8266 chip with at least two boot modes — the normal mode and the programming/flash mode. The latter refers to uploading any software (or firmware) to the ...

In order to use the ESP-01 Wi-Fi relay module, a programmer/programming adapter is required to program the ESP-01 module (see below). Also it is pretty easy to make your own programmer, or you can ...

Rather than having to solder a serial adapter to the chip to flash it, [Ryan] came up with a slick 3D printed programming jig that uses pogo pins.