download-clean-me

#!/bin/bash

set -e

function usage() {
    echo -n \
        "Usage: $(basename "$0") path_to_output_directory
Download BIOS update from ASUS, extract Intel Flash Descriptor/ME, neutralize, and shrink.
"
}

IFD_BIN_HASH="092caeee117de27c0eb30587defcb6449a33c7c325b6f3c47b5a7a79670b5c3f"
ME_BIN_HASH="8dda1e8360fbb2da05bfcd187f6e7b8a272a67d66bc0074bbfd1410eb35e3e17"

if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
    if [[ "${1:-}" == "--help" ]]; then
        usage
    else
        if [[ -z "${COREBOOT_DIR}" ]]; then
            echo "ERROR: No COREBOOT_DIR variable defined."
            exit 1
        fi

        output_dir="$(realpath "${1:-./}")"

        if [[ ! -f "${output_dir}/ifd.bin" || ! -f "${output_dir}/me.bin" ]]; then
            # Obtain Recovery BIOS capsule (.cap) file from ASUS.
            # https://www.asus.com/us/supportonly/p8z77-m%20pro/helpdesk_bios/
            pushd "$(mktemp -d)"

            curl -O https://dlcdnets.asus.com/pub/ASUS/mb/LGA1155/P8Z77-M_PRO/P8Z77-M-PRO-ASUS-2203.zip
            unzip P8Z77-M-PRO-ASUS-2203.zip

            # The first 2 KiB, or 2048 bytes, of the .cap file, consists of the
            # capsule file header. The remainder of the file contains the raw
            # ROM data.
            # https://web.archive.org/web/20230403201708/https://www.overclock.net/threads/asus-z10pe-d16-ws-owners-thread.1579548/page-30
            dd bs=1024 skip=2 if=P8Z77-M-PRO-ASUS-2203.CAP of=p8z77_m_pro_asus_2203.bin

            mv p8z77_m_pro_asus_2203.bin "${COREBOOT_DIR}/util/me_cleaner"

            popd

            # Neutralize Intel ME and resize the Intel Flash Descriptor (IFD)
            # layout.
            # https://github.com/corna/me_cleaner/wiki/External-flashing#neutralize-and-shrink-intel-me-useful-only-for-coreboot
            pushd "${COREBOOT_DIR}/util/me_cleaner"

            python me_cleaner.py -S -r -t -d -O out.bin -D ifd_shrinked.bin -M me_shrinked.bin ./p8z77_m_pro_asus_2203.bin

            # Clear each entry in the JEDEC/Vendor Specific Component
            # Capabilities (VSCC) table. The VSCC table starts at offset 0xDF0,
            # or 3568 bytes, into the file. The VSCC table contains eight
            # entries taking up 32 bytes in the unmodified Flash Descriptor. So,
            # we write 32 bytes worth of ones.
            printf '\xFF%.0s' {1..32} | dd of="./ifd_shrinked.bin" bs=1 seek=3568 count=32 conv=notrunc

            # Set VSCC Table Length (VTL) to zero. VTL is an 8-bit integer at
            # offset 0xEFD, or 3837 bytes, into the file.
            printf '\x00' | dd of="./ifd_shrinked.bin" bs=1 seek=3837 count=1 conv=notrunc

            mv ifd_shrinked.bin "${output_dir}/ifd.bin"
            mv me_shrinked.bin "${output_dir}/me.bin"
            rm ./*.bin

            popd
        fi

        if ! echo "${IFD_BIN_HASH} ${output_dir}/ifd.bin" | sha256sum --check; then
            echo "ERROR: SHA256 checksum for ifd.bin doesn't match."
            exit 1
        fi

        if ! echo "${ME_BIN_HASH} ${output_dir}/me.bin" | sha256sum --check; then
            echo "ERROR: SHA256 checksum for me.bin doesn't match."
            exit 1
        fi
    fi
fi