Index: src/uk/me/parabola/mkgmap/main/Main.java
===================================================================
--- src/uk/me/parabola/mkgmap/main/Main.java	(revision 3759)
+++ src/uk/me/parabola/mkgmap/main/Main.java	(working copy)
@@ -631,7 +631,7 @@
 	private void fileOptions(CommandArgs args) {
 		boolean indexOpt = args.exists("index");
 		boolean gmapsuppOpt = args.exists("gmapsupp");
-		boolean tdbOpt = args.exists("tdbfile");
+		boolean tdbOpt = args.exists("tdbfile") || args.exists("nsis");
 		boolean gmapiOpt = args.exists("gmapi");
 
 		if (tdbOpt || createTdbFiles){ 
@@ -647,7 +647,7 @@
 			addCombiner("gmapsupp", gmapBuilder);
 		}
 
-		if (indexOpt && (tdbOpt || !gmapsuppOpt)) {
+		if (indexOpt && tdbOpt) {
 			addCombiner("mdr", new MdrBuilder());
 			addCombiner("mdx", new MdxBuilder());
 		}