coreboot-x230

pre-built coreboot images and documentation on how to flash them for the Thinkpad X230. SeaBIOS is used as coreboot payload to be compatible with Windows and Linux systems.

Latest build (config overview and version info)

See our releases

• Lenovo's proprietary VGA BIOS ROM is executed in "secure" mode

coreboot

• We simply take coreboot's current state in it's master branch at the time we build a release image. That's the preferred way to use coreboot. The git revision we use is always included in the release.

Intel microcode

• revision 1f from 2018-02-07 (Intel package 20180312 not yet in coreboot upstream) under Intel's license

SeaBIOS

• version 1.11.0 from 2017-11-10 (part of coreboot upstream)

table of contents

• TL;DR
• Flashing for the first time
• How to update
• When do we do a release?
• How we build
• Why does this work
• Alternatives

TL;DR

Download a released image, connect your hardware SPI flasher to the "upper" 4MB chip in your X230, and do

 flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L3206E" -w x230_coreboot_seabios_example_top.rom

where linux_spi: is the example of using your SPI pins of, for example, a Raspberry Pi. A Bus Pirate with buspirate_spi or others connected to the host directly should be fine too.

Flashing for the first time

Especially for the first time, you must flash externally. See below for the details for using a Rapberry Pi, for example.

flashrom chip config

We use flashrom for flashing. Run flashrom -p <your_hardware> (for example flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 for the Raspberry Pi) to let flashrom detect the chip. It will probably list a few you need to choose from when flashing (by adding -c "<chipname>"). While there might be specific examples in the commands below, please review the chip model for your device. In case you are unsure what to specify, here's some examples we find out there:

4MB chip

• MX25L3206E seems to mostly be in use

8MB chip

• MX25L3206E/MX25L3208E is seen working with various X230 models.
• MX25L6406E/MX25L6408E is used in this guide
• EN25QH64 is used sometimes

EC firmware (optional)

Enter Lenovo's BIOS with F1 and check the embedded controller (EC) version to be 1.14 and upgrade using the latest bootable CD if it isn't. The EC cannot be upgraded when coreboot is installed. (In case a newer version should ever be available (I doubt it), you could temporarily flash back your original Lenovo BIOS image)

ifd unlock (necessary for internal flashing) and me_cleaner (optional)

The Intel Management Engine resides on the 8MB chip. We don't need to touch it for coreboot-upgrades in the future, but while opening up the Thinkpad anyways, we can save it and run ifdtool and me_cleaner on it:

  flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L6406E/MX25L6408E" -r ifdmegbe.rom
  flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L6406E/MX25L6408E" -r ifdmegbe2.rom
  diff ifdmegbe.rom ifdmegbe2.rom
  git clone https://github.com/corna/me_cleaner.git && cd me_cleaner
  ./me_cleaner.py -S -O ifdmegbe_meclean.rom ifdmegbe.rom
  ifdtool -u ifdmegbe_meclean.rom
  flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L6406E/MX25L6408E" -w ifdmegbe_meclean.rom.new

save the 4MB chip

(internally, memory of the two chips is mapped together, the 8MB being the lower part, but we can essientially ignore that)

For the first time, we have to save the original image, just like we did with the 8MB chip. It's important to keep this image somewhere safe:

  flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L3206E" -r top1.rom
  flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L3206E" -r top2.rom
  diff top1.rom top2.rom

How to update

When upgrading to a new release, only the "upper" 4MB chip has to be written. Download the latest release image we provide and flash it:

Example: Raspberry Pi 3

Here you'll flash externally, using a "Pomona 5250 8-pin SOIC test clip". You'll find one easily. This is how the X230's SPI connection looks on both chips:

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

       Edge (closest to you)

and the flashrom command you need, looks like so:

 flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=128 -c "MX25L3206E" -w x230_coreboot_seabios_example_top.rom

We run Raspbian and have the following setup

• Serial connection using a "USB to Serial" UART Adapter and picocom or minicom

• Yes, in this case you need a second PC connected to the RPi over UART

• in the SD Cards's /boot/config.txt file enable_uart=1 and dtparam=spi=on

• For flashrom we put spi_bcm2835 and spidev in /etc/modules

• Connect to a wifi or to network over ethernet to install flashrom

• only use the ...top.rom release file

• connect the Clip to the Raspberry Pi 3 (there are prettier images too:

       Edge of pi (furthest from you)
                   (UART)
     L           GND TX  RX                           CS
     E            |   |   |                           |
     F +---------------------------------------------------------------------------------+
     T |  x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x  |
       |  x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x   x  |
     E +----------------------------------^---^---^---^-------------------------------^--+
     D                                    |   |   |   |                               |
     G                                   3.3V MOSIMISO|                              GND
     E                                 (VCC)         CLK
       Body of Pi (closest to you)
  

Now you should be able to copy the image over to your Rasperry Pi and run the mentioned flashrom commands. One way to copy, is convertig it to ascii using uuencode (part of Debian's sharutils package) described below. This is a very direct, shady and slow way to copy file. Another way is of course using a USB Stick or scp :) (but you need even more hardware or a network).

    (convert)
host$ uuencode coreboot.rom coreboot.rom.ascii > coreboot.rom.ascii
    (transfer)
rpi$ cat > coreboot.rom.ascii
host$ pv coreboot.rom.ascii > /dev/ttyUSBX
    (wait)
rpi$ (CTRL-D)
    (convert back)
rpi$ uudecode -o coreboot.rom coreboot.rom.ascii
    (verify)
host$ sha1sum coreboot.rom
rpi$ sha1sum coreboot.rom

Example: internal

CAUTION: THIS IS NOT ENCOURAGED

• You have to have your 8MB chip flashed externally after ifdtool -u ifdmegbe.rom before this, once
• very convenient, but according to the flashrom manpage this is very dangerous!
• Boot Linux with the iomem=relaxed boot parameter (for example set in /etc/default/grub)
• download a released 4MB "top" rom image
• run prepare_internal_flashing.sh for generating all necessary files and instructions

When do we do a release?

Either when

• There is a new SeaBIOS release,
• There is a new Intel microcode release (for our CPU model),
• There is a coreboot issue that affects us, or
• We change the config

How we build

• Everything necessary to build coreboot (while only the top 4MB are usable of course) is included here
• The task of building coreboot is not too difficult
• When doing a release here, we always try to upload to coreboot's board status project
• If we add out-of-tree patches, we always post them for review upstream

Why does this work?

On the X230, there are 2 physical "BIOS" chips. The "upper" 4MB one holds the actual bios we can generate using coreboot, and the "lower" 8MB one holds the rest that you can modify yourself once, if you like, but strictly speaking, you don't need to touch it at all. What's this "rest"? Mainly a tiny binary used by the Ethernet card and the Intel Management Engine.

Alternatives

• Heads also releases pre-built flash images for the X230 - with way more sophisticated functionality.