diff --git a/bin/mbus-serial-scan-secondary.c b/bin/mbus-serial-scan-secondary.c
index 4b9e120..c382406 100755
--- a/bin/mbus-serial-scan-secondary.c
+++ b/bin/mbus-serial-scan-secondary.c
@@ -50,8 +50,8 @@ main(int argc, char **argv)
     }
     else if (argc == 4 && strcmp(argv[1], "-d") == 0)
     {
-        device = argv[1];   
-        addr_mask = strdup(argv[2]);
+        device = argv[2];   
+        addr_mask = strdup(argv[3]);
         debug = 1;
     }
     else if (argc == 4 && strcmp(argv[1], "-b") == 0)