How to read directly from Serial1? (baby steps into CASIC)

To work with CASIC it needs to read/write binary data into GPS chip.
We can write into Serial1. But.
When I try to read directly from it I get nothing.

Bangle.setGPSPower(0);
Bangle.removeAllListeners('GPS');
Bangle.removeAllListeners('GPS-raw');
Serial1.removeAllListeners();
Serial1.unsetup();
Serial1.setup(9600,{rx:D30,tx:D31});
Serial1.on('data',function(data){print("­ser:",data);});
D29.write(1); // turn GPS on

Here some output like bunch of pieces of NMEA messages is expected.
But nothing comes in.
When I set callback on 'GPS-raw' I receive them.
But it is not what I am looking for. I need to get raw bytes from Serial1.
'GPS-raw' does some parsing into string lines. That is what I am trying to avoid.