Did anyone manage to get SBAS reliable working on B2?

Thank for the reply. The post misses the checksum. The real code is:

function checksum(str) {
	var cs = 0;
  
	for (const c of str) {
		cs = cs ^ c.charCodeAt(0); //XOR
	}
  
	return cs.toString(16).toUpperCase().padStart(2, '0');
}

function configureSBAS() {
   const thisTime = new Date(); 
   let timeString = thisTime.toISOString();
	
  // SBAS satellite (SBAS satellite No. 1-19, corresponding to PRN 120-138
  var cmd = "PCAS15,4,FFFF"; //turn on satellites 1-16 of SBAS
  //var cmd = "PCAS15,4,7FFFF"; //turn on satellites 1-19 of SBAS

  cmd = "$" + cmd + "*" + checksum(cmd);
  Serial1.println(cmd);
  writeLogFile(timeString + ": " + cmd + "\n");
  
  SBASon = true;
}