Noob question, How to open the pill in s2+/s21a?

I am building lights for years but never had a LED torch since I only interested in headlamps
Today a friend brought me a tons of torches to fix including some Convoys and I manged to take the pill out but not to open it, is it reverse thread? any advice on how to open it?

Edit: I managed to open it using a "very sophisticated tool" I built, now' what is this MCU how do I flash it and where can I find a decent FW?