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Flashing coreboot on Gigabyte GA-G41M-ES2L with a ch341a USB programmer Tutorial

3 April 2019 16:59

In this tutorial, we will go through the steps to get coreboot compiled and flashed on Gigabyte GA-G41M-ES2L.



Things you need:

  • Gigabyte GA-G41M-ES2L
  • ch341a USB programmer
  • Pomona 5250 SOIC-8 clip
  • 6 x 10 cm female - female jumper wires

Files needed:


For more information about DejaVu Fonts, see:

For DejaVu Font license, see:

Packages needed to compile flashrom/coreboot/grub

sudo apt-get install git build-essential gnat flex bison libncurses5-dev wget libpci-dev libusb-dev libftdi1 libftdi-dev unifont zlib1g-dev

Compile flashrom

Clone flashrom git repository:

git clone

Compile flashrom:

cd flashrom
make -j4
sudo make install
sudo cp /usr/local/sbin/flashrom /usr/local/bin/

Compile GRUB

See 'Prerequisites' above for the font file needed.

Clone GRUB git repository:

git clone

Compile GRUB:

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

Create '' script file:

chmod +x

Paste the following in '':

#! /bin/bash

# ./ – 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

# 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}" \

# 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:


Connect ch341a USB programmer to flash chip

Connect ch341a USB programmer

Connect Pomona 5250 to flash chip named 'M_BIOS' like this:

    CS  5 --|  |-- 4  VCC
  MISO  6 --|  |-- 3  N/C
   N/C  7 --|  |-- 2  CLK
   GND  8 --|__|-- 1  MOSI

ch341a USB programmer connected

Read Factory BIOS

Read Factory BIOS 3 times:

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

Make sure checksums are identical:

sha512sum *.rom

Download coreboot

Download coreboot:


Extract coreboot:

tar xvf coreboot-4.10.tar.xz

Setup and compile coreboot

Enter coreboot folder:

cd coreboot-4.10

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

mainboard ---------|
                   |-Mainboard vendor (GIGABYTE)
                   |-Mainboard model (GA-G41M-ES2L)
                   |-ROM chip size (1024 KB (1 MB))
                   |-(0x100000) Size of CBFS filesystem in ROM
chipset -----------|
                   |-Include CPU microcode in CBFS (Do not include microcode updates)
Devices -----------|
                   |-Graphics initialization (Use libgfxinit)
                   |-    Legacy VGA text mode
Generic Drivers ---|
                   |-(XX:XX:XX:XX:XX:XX) Realtek rt8168 mac address
payload -----------|
                   |-Add a payload (An ELF executable payload)
                   |-"(grub2.elf)" Payload path and filename

Check the mac address for the onboard RT8168 network card and enter that in 'Generic Drivers -> Realtek rt8168 mac address'. My board is rev. 1.1 and it didn't find the onboard network card at all. If this happens to you, just leave default mac address as is and install a PCI or PCI express network card instead. I'm using a PCI network card 'D-Link DGE-528T' which uses RTL8169 kernel driver. Do some research beforehand to make sure your network card will work with default libre kernel drivers.

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

Compile coreboot:

make -j4

This will create 'build/coreboot.rom' image with the size of 1mb.

Add custom files to 'coreboot.rom' image

Add 'grub.cfg' to coreboot.rom. See 'Prerequisites' above for the file needed.

Make sure 'cbfstool' is built:

cd coreboot-4.10/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

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

Flash coreboot image

See 'Connect ch341a USB programmer to flash chip' for details on how to connect ch341a USB programmer.

Flash coreboot using ch341a USB programmer:

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

Additional parts needed

To build a desktop/server the following additional parts are needed:

Desktop case
Power supply

Here's the parts I used to build a server:

Desktop case: Fractal Design Define R6 Gunmetal
Power supply: Corsair RM750X 750W v2
CPU: Intel Core 2 Quad Q9550 2,83 GHz 12M
CPU Fan: Arctic Cooling Freezer 7 Pro rev.2
Memory: Corsair 2 x 2 GB DDR2 800 (PC2-6400) Memory
Network card: D-Link DGE-528T PCI (RTL8169 kernel driver)
Harddrive: Samsung 850 EVO 250GB SSD harddrive
PCI Express to USB 3.0 4-Port PCI Express Expansion Card Adapter Hub VIA 5Gbps
PCI Express SATA 3 Controller Card, 2 Port PCIe SATA III 6GB/s Internal Ada L80

The parts were carefully choosen so that the server would be as close to completely silent as possible and be able to run 100% free/libre software.

For a list of compatible CPU's (socket LGA 775), see:

The onboard network card might not work by default, and if so, just get a PCI or PCI Express network card.

Congratulations! We're done. Now you can install a libre distro such as Debian GNU/Linux.

Recommended reading