How to internally flash Libreboot on a ThinkPad

Introduction

The Libreboot documentation can be difficult to understand, and even more confusing to navigate.

This is a guide on how to internally flash Libreboot, on GM45 ThinkPads which have already had their BIOS flashed externally.

Quick setup

• Install flashrom and ich9gen (found here: ich9utils ¹)
  • ich9utils must be compiled, using make and gcc

• Download the latest Libreboot release

• On the target machine, generate a .bin file containing the MAC address of the ethernet interface ²

  # Determine the MAC address of the ethernet interface
  ip link
  # Enter the MAC address
  ich9gen --macaddress 00:1f:16:80:80:80
  

• Write the .bin file to the Libreboot ROM, noting the size of the flash chip

  • flashrom throws /dev/mem errors, unless the lpc_ich kernel module is removed

    sudo modprobe -r lpc_ich
    

  # Note the size of the flash chip, and write the appropriate .bin
  # 4m, 8m or 16m
  flashrom -p internal
  
  # Write the .bin to the ROM
  dd if=ich9fdgbe_8m.bin of=libreboot.rom bs=12k count=1 conv=notrunc
  

• Write the ROM to the flash chip

  • In addition, the flash chip must be specified using the -c option

  sudo flashrom -p internal:laptop=force_I_want_a_brick,boardmismatch=force -w libreboot.rom
  

• Dump the flashed ROM and compare the hashes

  # Make multiple dumps from the chip
  sudo flashrom -p internal:laptop=force_I_want_a_brick,boardmismatch=force -r dump1.bin
  sudo flashrom -p internal:laptop=force_I_want_a_brick,boardmismatch=force -r dump2.bin
  sudo flashrom -p internal:laptop=force_I_want_a_brick,boardmismatch=force -r dump3.bin
  # Compare the hashes against the ROM, ensuring that they are all the same
  sha1sum dump*.bin libreboot.rom
  

And done.