After peeling back some tape, there's one more Phillips #000 screw and the USB port assembly can be pulled out of the camera body.

The view onto the rest of the mainboard is almost unobstructed now and reveals that the microSD slot is actually soldered directly to the second part of the mainboard. A rather unusual choice, as that's often one of the first components to get "outsourced" from a mainboard when space is tight.