diff --git a/src/x86_64/Gstep.c b/src/x86_64/Gstep.c
index 8d5e1f6f..9fa0967b 100644
--- a/src/x86_64/Gstep.c
+++ b/src/x86_64/Gstep.c
@@ -201,7 +201,7 @@ unw_step (unw_cursor_t *cursor)
       if (DWARF_IS_NULL_LOC (c->dwarf.loc[RBP]))
         {
 	  ret = 0;
-	  Debug (2, "NULL %rbp loc, returning %d\n", ret);
+	  Debug (2, "NULL %%rbp loc, returning %d\n", ret);
 	  return ret;
         }
       if (!DWARF_IS_NULL_LOC (c->dwarf.loc[RIP]))