Flashing clip for Sonoff S31 (no pogo pins)

This clip accepts standard 2.54mm (0.1" pitch) male/female square-ended jumper wires with a length of 14mm. To assemble, insert the male ends of the jumper wires through the square hole in the cap, then insert those ends into the slots in the base and snap on the cap. Then insert the base/cap into the clip until it snaps in. Make sure you use jumper wires of the same type, with the same length pins, or they might not make a good connection with the pads on the circuit board.

To attach it to the circuit board, align the bottom of the clip underneath the corner of the board with the guides on the clip (see attached pic). Holding the S31 firmly, pull upward on the top of the clip with some force, then slide the pins in place over the pads on the board. Attach the female ends of the jumper wires to a USB serial adapter. Connect VCC to VCC, GND to GND, TX to RX, and RX to TX. Make sure your serial adapter is set to 3.3V! There are many videos online that show this process in more detail.