diff --git a/src/hactoolnet/CliParser.cs b/src/hactoolnet/CliParser.cs
index 13838592..1ebb1ffb 100644
--- a/src/hactoolnet/CliParser.cs
+++ b/src/hactoolnet/CliParser.cs
@@ -50,6 +50,12 @@ namespace hactoolnet
             new CliOption("sign", 0, (o, a) => o.SignSave = true),
             new CliOption("title", 1, (o, a) => o.TitleId = ParseTitleId(a[0])),
             new CliOption("bench", 1, (o, a) => o.BenchType = a[0]),
+
+            new CliOption("replacefile", 2, (o, a) =>
+            {
+                o.ReplaceFileDest = a[0];
+                o.ReplaceFileSource = a[1];
+            })
         };
 
         public static Options Parse(string[] args)
@@ -204,11 +210,12 @@ namespace hactoolnet
             sb.AppendLine("  --romfsdir <dir>     Specify RomFS directory path. (--title must be specified)");
             sb.AppendLine("  --savedir <dir>      Specify save file directory path.");
             sb.AppendLine("  -y, --verify         Verify all titles, or verify a single title if --title is set.");
-            sb.AppendLine("Savefile options:");
+            sb.AppendLine("Save data options:");
             sb.AppendLine("  --outdir <dir>       Specify directory path to save contents to.");
             sb.AppendLine("  --debugoutdir <dir>  Specify directory path to save intermediate data to for debugging.");
             sb.AppendLine("  --sign               Sign the save file. (Requires device_key in key file)");
             sb.AppendLine("  --listfiles          List files in save file.");
+            sb.AppendLine("  --replacefile <filename in save> <file> Replaces a file in the save data");
             sb.AppendLine("Keygen options:");
             sb.AppendLine("  --outdir <dir>       Specify directory path to save key files to.");
 
diff --git a/src/hactoolnet/Options.cs b/src/hactoolnet/Options.cs
index 6efce3d7..b7e3d697 100644
--- a/src/hactoolnet/Options.cs
+++ b/src/hactoolnet/Options.cs
@@ -33,6 +33,8 @@ namespace hactoolnet
         public string NormalDir;
         public string SecureDir;
         public string LogoDir;
+        public string ReplaceFileSource;
+        public string ReplaceFileDest;
         public bool ListApps;
         public bool ListTitles;
         public bool ListNcas;
diff --git a/src/hactoolnet/ProcessSave.cs b/src/hactoolnet/ProcessSave.cs
index af740d2c..1fab9fe9 100644
--- a/src/hactoolnet/ProcessSave.cs
+++ b/src/hactoolnet/ProcessSave.cs
@@ -94,6 +94,39 @@ namespace hactoolnet
                     duplexDataB.WriteAllBytes(Path.Combine(duplexDir, "DataB"), ctx.Logger);
                 }
 
+                if (ctx.Options.ReplaceFileDest != null && ctx.Options.ReplaceFileSource != null)
+                {
+                    string destFilename = ctx.Options.ReplaceFileDest;
+                    if (!destFilename.StartsWith("/")) destFilename = '/' + destFilename;
+
+                    using (IStorage inFile = new FileStream(ctx.Options.ReplaceFileSource, FileMode.Open, FileAccess.Read).AsStorage(false))
+                    {
+                        using (IStorage outFile = save.OpenFile(destFilename))
+                        {
+                            if (inFile.Length != outFile.Length)
+                            {
+                                ctx.Logger.LogMessage($"Replacement file must be the same size as the original file. ({outFile.Length} bytes)");
+                                return;
+                            }
+
+                            inFile.CopyTo(outFile, ctx.Logger);
+
+                            ctx.Logger.LogMessage($"Replaced file {destFilename}");
+                        }
+                    }
+
+                    if (save.CommitHeader(ctx.Keyset))
+                    {
+                        ctx.Logger.LogMessage("Successfully signed save file");
+                    }
+                    else
+                    {
+                        ctx.Logger.LogMessage("ERROR: Unable to sign save file. Do you have all the required keys?");
+                    }
+
+                    return;
+                }
+
                 if (ctx.Options.SignSave)
                 {
                     if (save.CommitHeader(ctx.Keyset))
@@ -104,6 +137,8 @@ namespace hactoolnet
                     {
                         ctx.Logger.LogMessage("Unable to sign save file. Do you have all the required keys?");
                     }
+
+                    return;
                 }
 
                 if (ctx.Options.ListFiles)