updateFirm method
Implementation
Future<PrinterStatus> updateFirm(String filepath) async {
var params = {
"printerId": mPrinterId,
"printInfo": mPrinterInfo.toMap(),
"filePath" : filepath,
};
final Map resultMap = await _channel.invokeMethod("updateFirm", params);
PrinterStatus status = PrinterStatus.fromMap(resultMap);
return status;
}