diff --git a/tools/mkfs7 b/tools/mkfs7
index f5cf81e..8bd0776 100755
--- a/tools/mkfs7
+++ b/tools/mkfs7
@@ -130,7 +130,8 @@ sub allocate_blocks {
     }
     dprintf(
         "Allocated blocks for size %d: %d .. %d (%06o .. %06o)\n",
-	$numwords, $blklist[0], $blklist[-1], $blklist[0], $blklist[-1]);
+	$numwords, $blklist[0], $blklist[-1], $blklist[0], $blklist[-1])
+		if ($blklist[0]);
     return (@blklist);
 }