Flashing coreboot on a Lenovo Thinkpad X220 with a ch341a USB programmer Tutorial

Andreas — April 2, 2019

In this tutorial, we will go through the steps to get coreboot compiled and flashed on a Lenovo Thinkpad X220 laptop. We'll also change the Wifi card so that Wifi will work with a libre kernel driver.

Updated 2022-01-13: Use latest coreboot-4.15 release

Prerequisites

Things you need:

Lenovo Thinkpad X220
Atheros AR9382 AR5BHB116 Mini PCIE Dual Band Wifi card
ch341a USB programmer or Raspberry Pi
Pomona 5250 SOIC-8 clip
6 x 10 cm female - female jumper wires
Screwdriver

This tutorial assumes you're using a GNU/Linux distro and are familiar with how to use a terminal.

Debian GNU/Linux 11 (bullseye) was used to compile the coreboot image produced in this tutorial.

Files needed:

dejavusansmono.pf2
grub.cfg
background.jpg

For more information about DejaVu Fonts, see:
https://dejavu-fonts.github.io/

For DejaVu Font license, see:
https://dejavu-fonts.github.io/License.html

'background.jpg' is borrowed from the libreboot project and it's license information is as follows:

These images are based on http://libreboot.org/logo/logo.svg
which is Copyright 2014 Marcus Moeller and released under CC-0
https://creativecommons.org/publicdomain/zero/1.0/legalcode

Packages needed to compile flashrom/coreboot/grub

sudo apt-get build-dep flashrom grub
sudo apt-get install git build-essential gnat flex bison libncurses5-dev libfreetype-dev pkg-config unifont wget

Compile flashrom

Clone flashrom git repository:

git clone https://review.coreboot.org/flashrom.git

Compile flashrom:

cd flashrom
sudo make install
sudo cp /usr/local/sbin/flashrom /usr/local/bin/

Compile GRUB

See 'Prerequisites' above for the files needed.

Clone GRUB git repository:

git clone https://git.savannah.gnu.org/git/grub.git

Compile GRUB:

cd grub
./bootstrap
./configure --with-platform=coreboot
make -j4

Create 'pack-payload-minimal.sh' script file:

touch pack-payload-minimal.sh
chmod +x pack-payload-minimal.sh

Paste the following in 'pack-payload-minimal.sh':

#! /bin/bash

# ./pack-payload-minimal.sh – To be invoked within GRUB project folder, packs
# an executable elf payload file for the coreboot project, using just one
# keyboard layout file. Adapt “settings” to your needs. Specify a lighter
# pf2-fontfile if available on your system.

# settings
elf_output="grub2.elf"
#pf2_fontfile="unicode.pf2"
pf2_fontfile="dejavusansmono.pf2"
keyboard_layout="se"
grub_modules="cbfs"

# generate keyboard layout
ckbcomp "${keyboard_layout}" | ./grub-mklayout -o "${keyboard_layout}.gkb"

# pack the GRUB payload file
./grub-mkstandalone \
        --grub-mkimage=./grub-mkimage \
        -O i386-coreboot \
        -o "${elf_output}" \
        -d grub-core \
        --fonts= \
        --themes= \
        --locales= \
        --modules="${grub_modules}" \
        /boot/grub/grub.cfg=coreboot.cfg \
        /boot/grub/fonts/${pf2_fontfile}="${pf2_fontfile}" \
        /boot/grub/layouts/${keyboard_layout}.gkb="${keyboard_layout}.gkb"

# message
echo "Payload ${elf_output} has been packed with:"
echo " * fontfile: ${pf2_fontfile}"
echo " * keyboard layout: ${keyboard_layout}"
echo " * GRUB modules, to be preloaded: ${grub_modules}"

# code snippet suggestion
echo "Don't forget to add 'keymap ${keyboard_layout}' to your GRUB Configuration File."

# clean up
rm "${keyboard_layout}.gkb"

Execute the script to create 'grub2.elf' file:

./pack-payload-minimal.sh

Connect programmer to flash chip

See Setup Raspberry Pi for flashing with flashrom Tutorial if you're using a Raspberry Pi.

Remove the following parts to access the flash chip:

Battery
Keyboard
Palmrest

Connect ch341a USB programmer

Connect Pomona 5250 to flash chip like this:

Screen (furthest from you)
             __
  MOSI  5 --|  |-- 4  GND
   CLK  6 --|  |-- 3  N/C
   N/C  7 --|  |-- 2  MISO
  3.3v  8 --|__|-- 1  CS

   N/C = Not connected / Not used

   Edge (closest to you)

ch341a USB programmer connected

Read Factory BIOS

Read Factory BIOS 3 times if using ch341a:

sudo flashrom -p ch341a_spi -r factory_bios_01.rom -V
sudo flashrom -p ch341a_spi -r factory_bios_02.rom -V
sudo flashrom -p ch341a_spi -r factory_bios_03.rom -V

Read Factory BIOS 3 times if using Raspberry Pi:

sudo flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -r factory_bios_01.rom -V
sudo flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -r factory_bios_02.rom -V
sudo flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -r factory_bios_03.rom -V

Make sure checksums are identical:

sha512sum *.rom

Download coreboot

Download coreboot:

wget https://coreboot.org/releases/coreboot-4.15.tar.xz
wget https://coreboot.org/releases/coreboot-blobs-4.15.tar.xz

coreboot-blobs-4.15.tar.xz is needed for CPU microcode updates.

Extract coreboot and blobs needed:

tar xvf coreboot-4.15.tar.xz
tar xvf coreboot-blobs-4.15.tar.xz --strip-components=1 -C coreboot-4.15

Create folder to hold 'descriptor/gbe/me.bin' files:

mkdir -pv coreboot-4.15/3rdparty/blobs/mainboard/lenovo/x220/

Extract blob files from Factory BIOS (see 'flashrom/util/ich_descriptors_tool' folder:

cd ~/misc-src/flashrom/util/ich_descriptors_tool
./ich_descriptors_tool -f your/path/to/factory_bios.rom -d

Copy blob files to coreboot folder:

cp factory_bios.rom.Descriptor.bin ~/misc-src/coreboot-4.15/3rdparty/blobs/mainboard/lenovo/x220/descriptor.bin
cp factory_bios.rom.GbE.bin ~/misc-src/coreboot-4.15/3rdparty/blobs/mainboard/lenovo/x220/gbe.bin
cp factory_bios.rom.ME.bin ~/misc-src/coreboot-4.15/3rdparty/blobs/mainboard/lenovo/x220/me.bin

Setup and compile coreboot

Enter coreboot folder:

cd coreboot-4.15

Build toolchain needed first (this will take a long time, be patient):

make crossgcc-i386 CPUS=4

coreboot settings menu:

make menuconfig

Set the following options:

NOTE: Leave default values as is and specifically set the following
options:

mainboard -|
           |-Mainboard vendor (Lenovo)
           |-Mainboard model (ThinkPad X220)
           |-ROM chip size (8192 KB (8 MB))
           |-(0x300000) Size of CBFS filesystem in ROM
chipset ---|
           |-Include CPU microcode in CBFS (Generate from tree)
           |-[*] Add Intel descriptor.bin file (leave default path as is)
           |-(3rdparty/blobs/mainboard/$(MAINBOARDDIR)/descriptor.bin) Path and filename of the descriptor.bin file
           |-[*] Add Intel ME/TXE firmware (leave default path as is)
           |-(3rdparty/blobs/mainboard/$(MAINBOARDDIR)/me.bin) Path to management engine firmware
           |-    [*] Verify the integrity of the supplied ME/TXE firmware
           |-    [*] Strip down the Intel ME/TXE firmware
           |-[*] Add gigabit ethernet firmware (leave default path as is)
           |-(3rdparty/blobs/mainboard/$(MAINBOARDDIR)/gbe.bin) Path to gigabit ethernet firmware
Devices ---|
           |-Graphics initialization (Use libgfxinit)
           |-Display
           |-    Framebuffer mode (Linear "high-resolution" framebuffer)
payload ---|
           |-Add a payload (An ELF executable payload)
           |-"(/path/to/grub/grub2.elf)" Payload path and filename

If you don't want to include CPU microcode updates:

chipset ---|
           |-Include CPU microcode in CBFS (Do not include microcode updates)

This will create a '.config' file containing all settings.

Compile coreboot:

make -j4

This will create 'build/coreboot.rom' image with the size of 8mb.

Add custom files to 'coreboot.rom' image

Add 'grub.cfg' and 'background.jpg' to coreboot.rom. See 'Prerequisites' above for the files needed.

Make sure 'cbfstool' is built:

cd coreboot-4.15/util/cbfstool
make -j4

Add custom GRUB configuration file:

./cbfstool ../../build/coreboot.rom add -t raw -n etc/grub.cfg -f your/path/to/grub.cfg

Check so that 'etc/grub.cfg' exists in coreboot.rom:

./cbfstool ../../build/coreboot.rom print

Add background image:

./cbfstool ../../build/coreboot.rom add -t raw -n background.jpg -f your/path/to/background.jpg

Check so that 'background.jpg' exists in coreboot.rom:

./cbfstool ../../build/coreboot.rom print

Done! Now it's time to flash the new 'coreboot.rom' image!

Flash coreboot image

See 'Connect programmer to flash chip' for details on how to connect programmer.

Flash coreboot using ch341a USB programmer:

sudo flashrom -p ch341a_spi -w coreboot.rom -V

Flash coreboot using Raspberry Pi programmer:

sudo flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -w coreboot.rom -V

Change Wifi card

Remove the following parts to access the Wifi card:

Battery
Keyboard
Palmrest

See 'Connect programmer to flash chip' for details on where the Wifi card is located.

Now you can install a libre distro such as Debian GNU/Linux.

Boot Debian GNU/Linux netinst iso from usb in GRUB2

Download Debian GNU/Linux netinst from here.

Check name of USB device:

sudo fdisk -l

Create bootable USB drive:

sudo dd bs=4M if=/path/to/debian-img.iso of=/dev/YOUR_USB status=progress oflag=sync

Start the computer up and in the GRUB2 menu press 'c' to enter command line and from there type the following:

set root='usb0'
linux /install.amd/vmlinuz
initrd /install.amd/initrd.gz
boot

Install Debian GNU/Linux normally and put GRUB2 on master boot record at the end of installation process. After reboot default option in GRUB2 menu on the flashchip will load GRUB2 on the AHCI HDD you installed on.

Download compiled coreboot image

The resulting coreboot image from this tutorial can be downloaded here:

lenovo-thinkpad-x220_coreboot-4-15-grub-master-with-cpu-microcode.rom

Congratulations! We’re done.

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