.read() hangs without error message

OpenCV v 3.2.0, as auto-built by opencv4nodejs, Running on Raspbian Lite.

Both a USB and the onboard camera are properly configured and verified as working via a test snapshot. It activates the USB camera, and the status light comes on, but it seems to hang. No error message, a try/catch doesn't get tripped. It just hangs. :-/ I've tried increasing the delay to allow more time to load, but it seems to never return a frame or an error.

`sleep.sleep(30);
console.log("Starting up");
cam.read(function(err, frame){
if(err){console.log(err)};
console.log("Grabbed first frame");
firstFrame = frame;
firstFrame.cvtColor('CV_BGR2GRAY');
firstFrame.gaussianBlur([21,21]);
});`

Any tips on increasing logging level for opencv4nodejs, or ideas on further troubleshooting? Thx in advance.