I am making a pinout for the pads on the bottom, hoping to find some extra pins we can use.
There are 2rows x 25 pads = 50 pads on the bottom (See blue text on image).
The headers + SD Card expose 2x16 + 8 = 40 pins.
So we have 10 extra pins to discover.
I already found a lot, but still missing some, I am hoping someone (maybe onion themselves) could help me identify the missing pins.
I made a sheet here: