T420-coreboot

I have followed these guides except that I have used an FT232H instead of a Raspberry Pi for reading and writing the BIOS chip MX25L6406E

• Lenovo T420 Coreboot W/Raspberry Pi
• t420-coreboot-guide

FT232H

Pinout

FTDI_FT2232H

Name	Color	Test clip pin#	FT232H pin#
/CS	Brown	1	AD3
MISO	Yellow	2	AD2
GND	Black	4	GND
MOSI	Orange	5	AD1
SCLK	Green	6	AD0
VCC	Red	8	+3.3V

Read out the BIOS

flashrom -p ft2232_spi:type=232H -c MX25L6406E/MX25L6408E -r factory1.rom

Write back the compiled BIOS

flashrom -p ft2232_spi:type=232H -c MX25L6406E/MX25L6408E -w coreboot.rom

LIBREBOOT

I looked at the guide below for inspiration; one can't follow it exactly any more as the libreboot project has refactored (especially the vendor files) since it was made. I have used a Debian Bookworm container on top of Proxmox -> 8 GB of RAM and a 15 GB drive (8 GB is too small)

• Installing libreboot on a ThinkPad T420

Download and build the development environment

git clone https://codeberg.org/libreboot/lbmk

Update flash after it has been flashed the first time

• How do I "edit grub to add iomem=relaxed"?

sudo flashrom -p internal:boardmismatch=force -c MX25L6406E/MX25L6408E -w coreboot.rom

Tested hardware

• Updated CPU to Intel i7-3632QM — with coreboot one can go to Ivy Bridge
• AX210 Mini PCIe WLAN 6E card
• BE200 Mini PCIe WLAN 7 card
• mSATA SanDisk U100 in the Mini PCIe slot next to the RAM in the bottom