diff --git a/src/bootstrap.sh b/src/bootstrap.sh
index 134cb10..04150b0 100755
--- a/src/bootstrap.sh
+++ b/src/bootstrap.sh
@@ -77,6 +77,9 @@ mkdir -p "${imageroot}"/var/db/repos
 mkdir -p "${imageroot}"/var/tmp
 [[ -e ${makeconf} ]] && cp "${makeconf}" "${imageroot}"/etc/portage/make.conf
 
+mkdir -p "${imageroot}"/etc/portage/env/sys-apps
+echo 'CFLAGS="${CFLAGS} -Oz"' >> "${imageroot}"/etc/portage/env/sys-apps/busybox
+
 # addrepoconfs [root]
 addrepoconfs() {
 	repoconf="${imageroot}"/etc/portage/repos.conf/gentoo.conf