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Skulls - Thinkpad X230.

seabios_bootmenu

Latest release

  • This directory's ./build.sh should produce the exact release image file (from a skulls git checkout). Get it from our release page
  • coreboot: We take coreboot's master branch at the time we build a release image.
  • microcode update: revision 20 from 2018-04-10 (includes mitigations for Spectre Variant 3a and 4)
  • SeaBIOS: version 1.11.2 from 2018-06-02
  • The only proprietary binary, the VGA BIOS is executed in "secure" mode (PCI_OPTION_ROM_RUN_YABEL)

table of contents

TL;DR

  1. run sudo ./x230_before_first_install.sh on your current X230 Linux system
  2. Power down, remove the battery. Remove the keyboard and palmrest. Connect a hardware flasher to an external PC (or a Raspberry Pi with a SPI 8-pin chip clip can directly be used), and run sudo ./external_install_bottom.sh on the lower chip and sudo ./external_install_top.sh on the top chip of the two.
  3. For updating later, run ./x230_skulls.sh. No need to disassemble.

And always use the latest released package. This will be tested. The git master branch is not meant to be stable. Use it for testing only.

First-time installation

before you begin

Before starting, run Linux on your X230, install dmidecode and run sudo ./x230_before_first_install.sh. It simply prints system information and helps you find out your RAM voltage. Make sure you have RAM that uses 1,5V, not 1,35V. Also make sure you have the latest skulls-x230 package release by running ./upgrade.sh.

original BIOS update / EC firmware (optional)

Before flashing coreboot, consider doing one original Lenovo upgrade process in case you're not running the latest version. This is not supported anymore, once you're running coreboot (You'd have to manually flash back your backup images first, see later chapters).

Also, this updates the BIOS and Embedded Controller (EC) firmware. The EC is not updated anymore, when running coreboot. The latest EC version is 1.14 and that's unlikely to change.

In case you're not running the latest BIOS version, either

  • use the latest original CD and burn it, or

  • use the same, only with a patched EC firmware that allows using any aftermarket-battery: By default, only original Lenovo batteries are allowed. Thanks to this project we can use Lenovo's bootable upgrade image, change it and create a bootable USB image, with an EC update that allows us to use any 3rd party aftermarket battery:

      sudo apt-get install build-essential git mtools libssl-dev
  git clone https://github.com/hamishcoleman/thinkpad-ec && cd thinkpad-ec
  make patch_disable_keyboard clean
  make patch_enable_battery clean
  make patched.x230.img

That's it. You can create a bootable USB stick: sudo dd if=patched.x230.img of=/dev/sdx and boot from it. Alternatively, burn patched.x230.iso to a CD. And make sure you have "legacy" boot set, not "UEFI" boot.

preparation: required hardware

open up the X230

Remove the 7 screws of your X230 to remove the keyboard (by pushing it towards the screen before lifting) and the palmrest. You'll find the chips using the photo below. This is how the SPI connection looks like on both of the X230's 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)

... choose one of the following supported flashing hardware examples:

Hardware Example: Raspberry Pi 3

A Raspberry Pi can directly be a flasher through it's I/O pins, see below. Use a test clip or hooks, see required hardware.

On the RPi we run Raspbian and have the following setup:

  • Connect to the console: Either

  • 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 ethernet to sudo apt-get install flashrom

  • 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)

Raspberry Pi at work

Now copy the Skulls release tarball over to the Rasperry Pi and continue on the Pi.

Hardware Example: CH341A based

The CH341A from Winchiphead, a USB interface chip, is used by some cheap memory programmers. The one we describe can be bought at aliexpress, but it's available elsewhere too. Also, we don't use the included 3,3V power output (provides too little power), but a separate power supply. If you don't have any, consider getting a AMS1117 based supply for a second USB port (like this or this).

  • Leave the P/S Jumper connected (programmer mode, 1a86:5512 USB device)
  • Connect 3,3V from your external supply to the Pomona clip's (or hook) VCC
  • Connect GND from your external supply to GND on your CH341A programmer
  • Connect your clip or hooks to the rest of the programmer's SPI pins
  • Connect the programmer (and power supply, if USB) to your PC's USB port

ch341a programmer with extra USB power supply

unpack the Skulls release archive

mkdir skulls
tar -xf skulls-x230-<version>.tar.xz -C skulls
cd skulls

ifd unlock and me_cleaner: the 8MB chip

The Intel Management Engine resides on the 8MB chip (at the bottom, closer to you). We don't need to touch it for coreboot-upgrades in the future, but to enable internal flashing, we need to unlock it once, and remove the Management Engine for security reasons:

sudo ./external_install_bottom.sh -m -k <backup.bin>

That's it. Keep the backup safe.

Background (just so you know):

  • The -m option above also runs me_cleaner -S before flashing back, see me_cleaner.
  • The -l option will (re-)lock your flash ROM, in case you want to force yourself (and others) to hardware-flashing.
  • Connecting an ethernet cable as a power-source for SPI (instead of the VCC pin) is not necessary (some other flashing how-to guides mention this). Setting a fixed (and low) SPI speed for flashrom offeres the same stability. Our scripts do this for you.

BIOS: the 4MB chip

sudo ./external_install_top.sh -i <release-image-file>.rom -k <backup>

That's it. Keep the backup safe, assemble and turn on the X230. coreboot will do hardware init and start SeaBIOS.

Updating

Only the "upper" 4MB chip has to be written. You can again flash externally, using external_install_top.sh just like the first time, see above.

Instead you can run the update directly on your X230 using Linux. That's of course very convenient - just install flashrom from your Linux distribution - but according to the flashrom manpage this is very dangerous:

  1. boot Linux with the iomem=relaxed boot parameter (for example in /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT)
  2. download the latest Skulls release tarball and unpack it
  3. run sudo ./x230_skulls.sh for generating all necessary files and instructions

Moving to Heads

Heads is an alternative BIOS system with advanced security features. It's more complicated to use though. When having Skulls installed, installing Heads is as easy as updating Skulls. You can directly start using it:

  • build Heads
  • boot Linux with the iomem=relaxed boot parameter
  • copy Heads' 12M image file build/x230/coreboot.rom to Skulls' x230 directory
  • run sudo ./x230_heads.sh

That's it. Heads is a completely different project. Please read the documentation for how to use it and report bugs over there

Switching back to Skulls is the same as updating. Just run ./x230_skulls.sh.

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.