There's been an attempt to determine the pin-out at another forum,
https://forum.xda-developers.com/showth ... ?t=2270287
Note that with some devices, the plastic teeth left and right to the pins can have pins, too.
The pin numbering in the answer refers to the image of the backside of the connector, where they are labelled.
For cross checking, you should measure the voltages of the pins. On the host side, USB pins should be pulled down to GND by 15 kOhms each (says the USB standard). So they should have 0V when reading voltage, 15 kOhms between them and GND when measuring continuity, and 30 kOhms between each other.