diff --git a/src/CloudInit.ConfigDrive.Core/UserDataSerializer.cs b/src/CloudInit.ConfigDrive.Core/UserDataSerializer.cs
index 22c1dac..6590c61 100644
--- a/src/CloudInit.ConfigDrive.Core/UserDataSerializer.cs
+++ b/src/CloudInit.ConfigDrive.Core/UserDataSerializer.cs
@@ -12,26 +12,32 @@ public class UserDataSerializer : IUserDataSerializer
         public async Task<Stream> SerializeUserData(IEnumerable<UserData> userData, UserDataOptions options)
         {
             var sb = new StringBuilder();
-            sb.AppendLine("From nobody Fri Jan  11 07:00:00 1980");
-            sb.AppendLine("Content-Type: multipart/mixed; boundary=\"==BOUNDARY==\"");
-            sb.AppendLine("MIME-Version: 1.0");
+            
+            sb.Append("From nobody Fri Jan  11 07:00:00 1980\n");
+            sb.Append("Content-Type: multipart/mixed; boundary=\"==BOUNDARY==\"\n");
+            sb.Append("MIME-Version: 1.0\n");
 
             foreach (var data in userData)
             {
-                sb.AppendLine("--==BOUNDARY==");
-                sb.AppendLine("MIME-Version: 1.0");
+                sb.Append("--==BOUNDARY==\n");
+                sb.Append("MIME-Version: 1.0\n");
 
 
-                sb.AppendLine($"Content-Type: {data.ContentType.Name}; charset=\"{data.Encoding.BodyName}\"");
+                sb.Append($"Content-Type: {data.ContentType.Name}; charset=\"{data.Encoding.BodyName}\"\n");
 
-                var contentString = data.Content;
+                if(!string.IsNullOrWhiteSpace(data.FileName))
+                    sb.Append($"Content-Disposition: attachment; filename=\"{data.FileName}\"\n");
+
+                var contentString = data.Content.Replace("\r\n", "\n");
                 if (options.Base64Encode)
                 {
-                    contentString = Convert.ToBase64String(data.Encoding.GetBytes(contentString), Base64FormattingOptions.InsertLineBreaks);
-                    sb.AppendLine("Content-Transfer-Encoding: base64");
+                    contentString = Convert
+                        .ToBase64String(data.Encoding.GetBytes(contentString), Base64FormattingOptions.InsertLineBreaks)
+                        .Replace("\r\n", "\n");
+                    sb.Append("Content-Transfer-Encoding: base64\n");
                 }
 
-                sb.AppendLine(contentString);
+                sb.Append(contentString+ "\n");
 
 
             }
diff --git a/src/CloudInit.ConfigDrive.Primitives/UserData.cs b/src/CloudInit.ConfigDrive.Primitives/UserData.cs
index b7bb28a..da56bcf 100644
--- a/src/CloudInit.ConfigDrive.Primitives/UserData.cs
+++ b/src/CloudInit.ConfigDrive.Primitives/UserData.cs
@@ -2,9 +2,11 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
+using JetBrains.Annotations;
 
 namespace Dbosoft.CloudInit.ConfigDrive
 {
+    [PublicAPI]
     public class UserData
     {
         public UserData(UserDataContentType contentType, string content, Encoding encoding)
@@ -14,9 +16,17 @@ public UserData(UserDataContentType contentType, string content, Encoding encodi
             Encoding = encoding;
         }
 
-        public UserDataContentType ContentType { get; set; }
-        public string Content { get; set; }
-        public Encoding Encoding { get; set; }
+        public UserData(UserDataContentType contentType, string content, string fileName, Encoding encoding)
+        {
+            ContentType = contentType;
+            Content = content;
+            FileName = fileName;
+            Encoding = encoding;
+        }
 
+        public UserDataContentType ContentType { get; set; }
+        public string Content { get;  }
+        public Encoding Encoding { get;  }
+        public string? FileName { get; set; }
     }
 }
\ No newline at end of file
diff --git a/test/CloudInit.ConfigDrive.Core.Test/UserDataSerializerTests.cs b/test/CloudInit.ConfigDrive.Core.Test/UserDataSerializerTests.cs
index 531334c..d29416d 100644
--- a/test/CloudInit.ConfigDrive.Core.Test/UserDataSerializerTests.cs
+++ b/test/CloudInit.ConfigDrive.Core.Test/UserDataSerializerTests.cs
@@ -29,7 +29,7 @@ public async Task WritesFixedHeader()
         Assert.Equal(@"From nobody Fri Jan  11 07:00:00 1980
 Content-Type: multipart/mixed; boundary=""==BOUNDARY==""
 MIME-Version: 1.0
-", act);
+".Replace("\r\n", "\n"), act);
     }
 
     [Fact]
@@ -59,7 +59,7 @@ await serializer.SerializeUserData(
 MIME-Version: 1.0
 Content-Type: text/cloud-config; charset=""us-ascii""
 some config
-", act);
+".Replace("\r\n", "\n"), act);
     }
 
     [Fact]
@@ -90,7 +90,7 @@ await serializer.SerializeUserData(
 Content-Type: text/cloud-config; charset=""us-ascii""
 Content-Transfer-Encoding: base64
 {Convert.ToBase64String(Encoding.ASCII.GetBytes("some config"), Base64FormattingOptions.InsertLineBreaks)}
-", act);
+".Replace("\r\n", "\n"), act);
 
     }
 
@@ -118,7 +118,7 @@ public async Task GZipCompressed()
         Assert.Equal(@"From nobody Fri Jan  11 07:00:00 1980
 Content-Type: multipart/mixed; boundary=""==BOUNDARY==""
 MIME-Version: 1.0
-", act);
+".Replace("\r\n", "\n"), act);
 
     }