diff --git a/util-linux.spec b/util-linux.spec
index 6b3821f..7bd2b7c 100644
--- a/util-linux.spec
+++ b/util-linux.spec
@@ -44,7 +44,8 @@ BuildRequires: librtas-devel
 #BuildRequires: autoconf
 #BuildRequires: automake
 #BuildRequires: libtool
-#BuildRequires: bison
+BuildRequires: bison
+BuildRequires: flex
 
 ### Sources
 Source0: https://www.kernel.org/pub/linux/utils/util-linux/v%{upstream_major}/util-linux-%{upstream_version}.tar.xz