Pogo pin headers make for a very easy job programming the Sonoff S31.
What I bought (not an affiliate link): https://www.amazon.com/dp/B09NHQY8R2/
STEP file: https://github.com/techdregs/Pogo_Pro...
=== Timestamps ===
0:00 Introduction
0:54 Pogo Pin Headers
1:54 How I made mine...