diff --git a/index.html b/index.html
index fae6e4ad..bacdc380 100644
--- a/index.html
+++ b/index.html
@@ -89,7 +89,7 @@ if (window.location.host.endsWith('8bitworkshop.com')) {
           <li><a class="dropdown-item" href="#" id="item_download_rom">Download ROM Image</a></li>
           <li><a class="dropdown-item" href="#" id="item_download_zip">Download Project as ZIP</a></li>
           <li><a class="dropdown-item" href="#" id="item_download_allzip">Download All Changes as ZIP</a></li>
-          <li><a class="dropdown-item" href="#" id="item_download_sym">Download Debug Symbols (.mlb)</a></li>
+          <li><a class="dropdown-item" href="#" id="item_download_sym">Download Debug Symbols</a></li>
         </ul>
       </li>
       <li class="dropdown dropdown-submenu">
diff --git a/src/common/baseplatform.ts b/src/common/baseplatform.ts
index 6f6483b3..5d471230 100644
--- a/src/common/baseplatform.ts
+++ b/src/common/baseplatform.ts
@@ -151,6 +151,7 @@ export interface Platform {
   sourceFileFetch?: (path:string) => FileData;
 
   getDownloadFile?() : {extension:string, blob:Blob};
+  getDebugSymbolFile?() : {extension:string, blob:Blob};
 }
 
 export interface Preset {
diff --git a/src/ide/ui.ts b/src/ide/ui.ts
index 12b403fa..e4b9f4ab 100644
--- a/src/ide/ui.ts
+++ b/src/ide/ui.ts
@@ -1142,38 +1142,15 @@ async function _downloadProjectZipFile(e) {
 }
 
 function _downloadSymFile(e) {
-  var sym = platform.debugSymbols.addr2symbol;
-  var text = "";
-  $.each(sym, function(k, v) {
-    let symType;
-    if (k < 0x2000) {
-      k = k % 0x800;
-      symType = "R";
-    } else if (k < 0x6000) symType = "G";
-    else if (k < 0x8000) {
-      k = k - 0x6000;
-      symType = "S";
-    } else { 
-      k = k - 0x8000;
-      symType = "P";
-    }
-    let addr = Number(k).toString(16).padStart(4, '0').toUpperCase();
-    // Mesen doesn't allow lables to start with digits
-    if (v[0] >= '0' && v[0] <= '9') {
-    v = "L" + v;
-    }
-    // nor does it allow dots
-    v = v.replaceAll('.', '_');
-    text += `${symType}:${addr}:${v}\n`;
-  });
-  
+  let symfile = platform.getDebugSymbolFile && platform.getDebugSymbolFile();
+  if (!symfile) {
+    alertError("This project does not have debug information.");
+    return;
+  }  
   var prefix = getFilenamePrefix(getCurrentMainFilename());
-  var blob = new Blob([text], {type:"text/plain;charset=utf-8"});
-  saveAs(blob, prefix + ".mlb", {autoBom:false});
-
+  saveAs(symfile.blob, prefix + symfile.extension, {autoBom:false});
 }
 
-
 async function _downloadAllFilesZipFile(e) {
   var zip = await newJSZip();
   var keys = await store.keys();
diff --git a/src/platform/nes.ts b/src/platform/nes.ts
index fe7859bc..e4720a88 100644
--- a/src/platform/nes.ts
+++ b/src/platform/nes.ts
@@ -486,6 +486,37 @@ class JSNESPlatform extends Base6502Platform implements Platform, Probeable {
   showHelp(tool:string, ident:string) {
     window.open("https://8bitworkshop.com/docs/platforms/nes/", "_help"); // TODO
   }
+
+  getDebugSymbolFile() {
+    var sym = this.debugSymbols.addr2symbol;
+    var text = "";
+    $.each(sym, function(k, v) {
+      let symType;
+      if (k < 0x2000) {
+        k = k % 0x800;
+        symType = "R";
+      } else if (k < 0x6000) symType = "G";
+      else if (k < 0x8000) {
+        k = k - 0x6000;
+        symType = "S";
+      } else { 
+        k = k - 0x8000;
+        symType = "P";
+      }
+      let addr = Number(k).toString(16).padStart(4, '0').toUpperCase();
+      // Mesen doesn't allow lables to start with digits
+      if (v[0] >= '0' && v[0] <= '9') {
+      v = "L" + v;
+      }
+      // nor does it allow dots
+      v = (v as any).replaceAll('.', '_');
+      text += `${symType}:${addr}:${v}\n`;
+    });
+    return {
+      extension:".mlb", 
+      blob: new Blob([text], {type:"text/plain"})
+    };
+  }
 }
 
 /// MAME support
@@ -522,6 +553,7 @@ class NESMAMEPlatform extends BaseMAME6502Platform implements Platform {
   getToolForFilename = getToolForFilename_6502;
   getOpcodeMetadata = getOpcodeMetadata_6502;
   getDefaultExtension() { return ".c"; };
+
 }
 
 ///