diff --git a/chroot_version_hooks.d/9_board_makeconf_setup b/chroot_version_hooks.d/9_board_makeconf_setup
new file mode 100644
index 0000000000..c8b724727b
--- /dev/null
+++ b/chroot_version_hooks.d/9_board_makeconf_setup
@@ -0,0 +1,24 @@
+# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Make sure the BOARD_USE variable is set in make.conf.board_setup.
+for board_root in /build/*; do
+  board=$(basename "${board_root}")
+
+  # Make sure this is a real board by looking for emerge-<board>.
+  emerge_board=$(which emerge-${board} 2>/dev/null || true)
+  if [ -x "${emerge_board}" ]; then
+    board_setup="/build/${board}/etc/make.conf.board_setup"
+    if [ -f "${board_setup}" ] && ! grep -q BOARD_USE "${board_setup}"; then
+      sudo_append "${board_setup}" << EOF
+BOARD_USE="${board}"
+EOF
+      info "Added BOARD_USE to ${board_setup}"
+    fi
+  fi
+done
+
+info "Chroot upgraded to version 9: Insert BOARD_USE in make.conf.board_setup"
+exit 0
+