I am trying to reverse engineer a cheap Chinese Hi3518ev200 based camera for quite some time now. I have successfully located the UART used for the serial console (3 pins lower left on the picture), but am struggling finding an USB port the operating system detects. Maybe it's just not connected.
However, a 4 holes port is available but I can't figure out what it could be, upper right on the picture

Both pairs output continuous 1.8v when the board is powered on, probed in both a multi meter and a basic oscilloscope.
Any idea on what this port could be?