pkg.cs

using System;
using System.IO;

namespace pkg_merge
{
	public class Program
	{
		static void Main(string[] args)
		{
			Directory.GetFiles("pkgs");

			byte[] buffer = new byte[1024 * 1024];

			using (var br = new BinaryReader(File.Open("pkgs/UP2050-CUSA01340_00-DUNDEF2000000PS4-A0151-V0100_0.pkg", FileMode.Open)))
			using (var br2 = new BinaryWriter(File.Open("pkgs/test.pkg", FileMode.Append)))
			{
				long fileSize = br.BaseStream.Length;
				long totalRead = 0;
				while (totalRead < fileSize)
				{
					var read = br.Read(buffer, 0, buffer.Length);
					br2.Write(buffer, 0, buffer.Length);
					totalRead += read;
					Console.Write($"Read {totalRead}/{fileSize} bytes\r");
				}
			}
			Console.WriteLine("\r\ndone");
			Console.ReadKey();
		}
	}
}