blob: 1c5f3bdd3869325e44dcb6d44595537d240e7ddc [file] [log] [blame]
# 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.
# This script converts a Chrome OS device to a pre-factory-install state:
# * Firmware write protect disabled
# * H2O BIOS, with RO VPD area copied from the current BIOS
# * Original EC firmware
# * Blank SSD (no GPT)
# Minimal usage:
# -b H2OBIOS.bin -e
SCRIPT_BASE="$(dirname "$0")"
load_shflags || exit 1
# Constants used by DEFINE_*
# DEFINE_string name default_value description flag
DEFINE_string bios "" "Path of system firmware (BIOS) binary to write" "b"
DEFINE_string ec "" "Path of EC shellball to execute" "e"
DEFINE_string backup_dir "" "Path of directory in whoch to store backups" "k"
DEFINE_string asset_tag "unspecified_tag" \
"Asset tag of device, used to name backups" "a"
DEFINE_string ssd "/dev/sda" "Path to SSD / target drive" "s"
DEFINE_boolean wipe_ssd $FLAGS_TRUE "Wipe SSD after firmware updates" ""
DEFINE_boolean nothing $FLAGS_FALSE \
"Print commands but do not modify device" "n"
# Parse command line
FLAGS "$@" || exit 1
eval set -- "$FLAGS_ARGV"
# Globals
# ----------------------------------------------------------------------------
set -e
# Flashrom commands with device overrides
FLASHROM_BIOS="flashrom -p internal:bus=spi"
FLASHROM_EC="flashrom -p internal:bus=lpc"
# A log file to keep the output results of executed command
# Temporary Work directory
# Functions
# ----------------------------------------------------------------------------
# Error message for write protect disable failure, with reminder
wp_error() {
local which_rom=$1
echo "ERROR: Unable to disable $which_rom write protect: $*" 1>&2
echo "Is hardware write protect still enabled?" 1>&2
exit 1
# Disable write protect for an EEPROM
disable_wp() {
local which_rom=$1 # EC or BIOS
local flash_rom="$*" # Flashrom command to use
debug_msg "Disabling $which_rom write protect"
$NOTHING ${flash_rom} --wp-disable || wp_error "$which_rom" "--wp-disable"
$NOTHING ${flash_rom} --wp-range 0 0 || wp_error "$which_rom" "--wp-range"
# WP status bits should report WP: status: 0x00
local wp_status="$(${flash_rom} --wp-status | grep "WP: status:")"
if [ "$wp_status" != "WP: status: 0x00" ]; then
if [ "$FLAGS_nothing" = $FLAGS_FALSE ]; then
wp_error "$which_rom" "$wp_status"
# Back up current firmware and partition table
make_backups() {
debug_msg "Backing up current firmware to $FLAGS_backup_dir"
mkdir -p "$FLAGS_backup_dir"
cp "$OLD_BIOS" "$FLAGS_backup_dir/$FLAGS_asset_tag.bios.bin"
${FLASHROM_EC} -r "$FLAGS_backup_dir/$"
# Copy the VPD info from RAM, since we can't extract it as text
# from the BIOS binary. Failure of this is only a warning, since
# the information is still in the old BIOS.
mosys vpd print all > "$FLAGS_backup_dir/$FLAGS_asset_tag.vpd.txt" ||
echo "WARNING: unable to save VPD as text."
# Copy the first part of the drive, so we can recreate the partition
# table.
local gpt_backup="$FLAGS_backup_dir/$FLAGS_asset_tag.gpt.bin"
debug_msg "Backing up current GPT table."
dd if="$FLAGS_ssd" of="$gpt_backup" bs=512 count=34
# Add a script to restore the BIOS and GPT
local restore_script="$FLAGS_backup_dir/$"
cat >"$restore_script" <<EOF
echo "Restoring BIOS"
${FLASHROM_BIOS} -w "$FLAGS_asset_tag.bios.bin"
echo "Restoring EC"
${FLASHROM_EC} -w "$"
echo "Restoring GPT"
dd of="$FLAGS_ssd" if="$FLAGS_asset_tag.gpt.bin" conv=notrunc
echo "To restore original BIOS and SSD:"
echo " cd $FLAGS_backup_dir && sh $"
# Main
# ----------------------------------------------------------------------------
main() {
# Make sure the files we were passed exist
[ -n "$FLAGS_bios" ] || err_die "Please specify a BIOS file (-b bios.bin)"
[ -n "$FLAGS_ec" ] || err_die "Please specify an EC updater (-e"
ensure_files_exist "$FLAGS_bios" "$FLAGS_ec" || exit 1
# If --nothing was specified, keep flashrom from writing
if [ "$FLAGS_nothing" = $FLAGS_TRUE ]; then
NOTHING="echo Not executing: "
# Stop update engine before calling flashrom. Multiple copies of flashrom
# interfere with each other.
debug_msg "Stopping update engine"
initctl stop update-engine
# Read the current firmware
debug_msg "Reading BIOS from EEPROM"
# Copy current info to the backup dir, if specified
if [ -n "$FLAGS_backup_dir" ]; then
# Find the RO VPD area in the current firmware
local t="$(mosys -k eeprom map "$OLD_BIOS" | grep 'RO VPD')"
local vpd_offset="$(echo $t | sed 's/.*area_offset="\([^"]*\)" .*/\1/' )"
local vpd_size="$(echo $t | sed 's/.*area_size="\([^"]*\)" .*/\1/' )"
debug_msg "Found VPD at offset $vpd_offset size $vpd_size"
# Convert offset and size to decimal, since dd doesn't grok hex
vpd_offset="$(printf "%d" $vpd_offset)"
vpd_size="$(printf "%d" $vpd_size)"
debug_msg "In decimal, VPD is at offset $vpd_offset size $vpd_size"
# Copy the RO VPD from the old firmware to the new firmware
debug_msg "Copying VPD from old firmware to new firmware"
cp "$FLAGS_bios" "$NEW_BIOS"
dd bs=1 seek=$vpd_offset skip=$vpd_offset count=$vpd_size conv=notrunc \
if="$OLD_BIOS" of="$NEW_BIOS" || err_die "Unable to copy RO VPD"
# Disable write protect
disable_wp "EC" ${FLASHROM_EC}
disable_wp "BIOS" ${FLASHROM_BIOS}
# Write new firmware
debug_msg "Writing EC"
# TODO: if EC file ends in .bin, use flashrom to write it directly?
$NOTHING sh "$FLAGS_ec" --factory || err_die "Unable to write EC"
debug_msg "Writing BIOS"
$NOTHING ${FLASHROM_BIOS} -w "$NEW_BIOS" || err_die "Unable to write BIOS"
# Wipe SSD
if [ "$FLAGS_wipe_ssd" = $FLAGS_TRUE ]; then
debug_msg "Wiping SSD"
$NOTHING cgpt create -z "$FLAGS_ssd" || err_die "Unable to wipe SSD"
# Leave the update engine stopped. We've mucked with the firmware
# and SSD contents, so we shouldn't be attempting an autoupdate this
# boot anyway.