VB.NET - FTP upload/download integrity issues - vb.net

Question

I have a Windows service that periodically uploads files to an FTP server, and will then redownload the file to check that the bytes match exactly. For most files it seems ok, but one of the files we're using recently is a 10mb CSV file and the files are always slightly different (by a couple of bytes).
Below are the upload, download and file compare methods. Note that the Download is setting UseBinary as true but the upload isn't - could this be why?
public string Upload(FileInfo fi, string targetFilename)
{
//copy the file specified to target file: target file can be full path or just filename (uses current dir)
//1. check target
string target;
if (targetFilename.Trim() == "")
{
//Blank target: use source filename & current dir
target = this.CurrentDirectory + fi.Name;
}
else if (targetFilename.Contains("/"))
{
//If contains / treat as a full path
target = AdjustDir(targetFilename);
}
else
{
//otherwise treat as filename only, use current directory
target = CurrentDirectory + targetFilename;
}
string URI = Hostname + target;
//perform copy
System.Net.FtpWebRequest ftp = GetRequest(URI);
//Set request to upload a file in binary
ftp.Method = System.Net.WebRequestMethods.Ftp.UploadFile;
ftp.UseBinary = false;
//Notify FTP of the expected size
ftp.ContentLength = fi.Length;
//create byte array to store: ensure at least 1 byte!
const int BufferSize = 2048;
byte[] content = new byte[BufferSize - 1 + 1];
int dataRead;
string result = null;
//open file for reading
using (FileStream fs = fi.OpenRead())
{
try
{
//open request to send
using (Stream rs = ftp.GetRequestStream())
{
do
{
dataRead = fs.Read(content, 0, BufferSize);
rs.Write(content, 0, dataRead);
} while (!(dataRead < BufferSize));
rs.Close();
}
}
catch (Exception x)
{
result = URI + " - " + x.ToString();
}
finally
{
//ensure file closed
fs.Close();
}
}
ftp = null;
return result;
}
#endregion
public bool Download(string sourceFilename, FileInfo targetFI, bool PermitOverwrite)
{
//1. check target
if (targetFI.Exists && !(PermitOverwrite))
{
throw (new ApplicationException("Target file already exists"));
}
//2. check source
string target;
if (sourceFilename.Trim() == "")
{
throw (new ApplicationException("File not specified"));
}
else if (sourceFilename.Contains("/"))
{
//treat as a full path
target = AdjustDir(sourceFilename);
}
else
{
//treat as filename only, use current directory
target = CurrentDirectory + sourceFilename;
}
string URI = Hostname + target;
//3. perform copy
System.Net.FtpWebRequest ftp = GetRequest(URI);
//Set request to download a file in binary mode
ftp.Method = System.Net.WebRequestMethods.Ftp.DownloadFile;
ftp.UseBinary = true;
ftp.UsePassive = false;
//open request and get response stream
using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse())
{
using (Stream responseStream = response.GetResponseStream())
{
//loop to read & write to file
using (FileStream fs = targetFI.OpenWrite())
{
try
{
byte[] buffer = new byte[2048];
int read = 0;
do
{
read = responseStream.Read(buffer, 0, buffer.Length);
fs.Write(buffer, 0, read);
} while (!(read == 0));
responseStream.Close();
fs.Flush();
fs.Close();
}
catch (Exception)
{
//catch error and delete file only partially downloaded
fs.Close();
//delete target file as it's incomplete
targetFI.Delete();
throw;
}
}
responseStream.Close();
}
response.Close();
}
return true;
}
Public Function FileCompare(ByVal file1 As String, ByVal file2 As String) As Boolean
' Checks to see if two files are the same
Dim file1byte As Integer
Dim file2byte As Integer
Dim fs1 As FileStream
Dim fs2 As FileStream
If file1 = file2 Then
Return True
End If
fs1 = New FileStream(file1, FileMode.Open)
fs2 = New FileStream(file2, FileMode.Open)
' Simple length test
If fs1.Length <> fs2.Length Then
fs1.Close()
fs2.Close()
Return False
End If
Do
file1byte = fs1.ReadByte()
file2byte = fs2.ReadByte()
Loop While file1byte = file2byte And file1byte <> -1
fs1.Close()
fs2.Close()
Return ((file1byte - file2byte) = 0)
End Function