diff --git a/buildbot/buildbot_steps.sh b/buildbot/buildbot_steps.sh
index 40c22f8..7059619 100755
--- a/buildbot/buildbot_steps.sh
+++ b/buildbot/buildbot_steps.sh
@@ -39,10 +39,10 @@ function sed_enabled_ipxe_features() {
                   CERT_CMD
         do
         sed -ri \
-          "s/^\\/+#define[[:space:]]+$OPTION[[:space:]/#define $OPTION /g" \
+          "s/^\\/+#define[[:space:]]+$OPTION[[:space:]]/#define $OPTION /g" \
           "${ipxe_src_dir}/src/config/general.h"
 	sed -ri
-          "s/^#undef[[:space:]]+$OPTION[[:space:]/#define $OPTION /g" \
+          "s/^#undef[[:space:]]+$OPTION[[:space:]]/#define $OPTION /g" \
           "${ipxe_src_dir}/src/config/general.h"
     done