Sending Assisted GNSS (A-GNSS) to Bangle 2 GPS (AT6558)

I assume you have sent these one by one manually.

No, after one first message is pushed, when response is captured, I check if it is ACK class. If it is, I call pushing of second message, and so on, until the buffer's end is reached.

var EPO=new DataView(
  require("Storage").readArrayBuffer("ble_epo_offline.bin"));
var i=0, h1=0, h2=0, len=0, cs=0, p=0, pe=0,s="";
function pushNextAGPSMessage(){
  while(i<EPO.byteLength){
  h1=EPO.getUint8(i);
  h2=EPO.getUint8(i+1);
  if(h1==0xBA && h2==0xCE){
    s="";
    len=EPO.getUint16(i+2,true)+10;
    p=i; pe=p+len;
    print("push ",h1,h2, p, len);
    while(p<pe){
      s+=",0x"+EPO.buffer[p].toString(16);
      Serial2.write(EPO.buffer[p]);
      p++;
    }
    print(s);
    print(prsMsgGPSEph({payload:EPO.buffer},i+6));
    i=p;
    return;
  }else{i++;}
  }
}

D29.write(0);
Serial2.removeAllListeners();
Serial2.setup(9600,{rx:D30,tx:D31});
Serial2.removeAllListeners();
var msg;
Serial2.on('data', function(data){
//print(data);
  msg=parseCASIC(data);
  if(i<EPO.byteLength && typeof msg != 'undefined' && msg.class==0x05){ 
    msg=undefined;
    while(Serial2.available()>0)print('A');
    pushNextAGPSMessage();
  }
});

D29.write(1);

Serial2.println("$PCAS03,0,0,0,0,0,0,0,0,0,,0,,,0*32");

i=0;
pushNextAGPSMessage();

this code is very experimental. And parseCASIC(data) is not here. it is part of CASIC module I am working on.