diff --git a/chroot_version_hooks.d/20_board_portage_bashrc b/chroot_version_hooks.d/20_board_portage_bashrc
new file mode 100644
index 0000000000..3606516961
--- /dev/null
+++ b/chroot_version_hooks.d/20_board_portage_bashrc
@@ -0,0 +1,9 @@
+# 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.
+
+# Punt the old board's /etc/portage/bashrc as we don't use it anymore,
+# and it conflicts with newer bashrc stacking.
+sudo rm -f /build/*/etc/portage/bashrc
+
+exit 0