grebllaw123d,
Not sure yet, but here's a link to a very good
photo of the L/H forward fuselage of a/c 811, which has the same colour scheme as the incident a/c 804. (See the second B787 photo on this link.)
The port is just below the first "7" of "787". It doesn't look very venturi-like, so might be a drain hole. (There seems to be a large venturi well below it, almost behind the nose leg.)