Board:lenovo/x220

Status

Thanks for your interest in Lenovo X220 port. Issues:

• no MRC cache (longer boot time)
• yellow USB port isn't powered in power-off state.
• Badly seated RAM may prevent booting (not really a problem but coreboot is more suspicious to this than vendor BIOS)

Tested (and works):

• RAM module combinations of 4G+0, 4G+4G
• S3 (Suspend to RAM)
• digitizer on x220t variant
• WLAN (first minipcie slot)
• Linux (through GRUB-as-payload)
• trackpoint
• Fn hotkeys
• Video (both internal and VGA, including native gfx init)
• touchpad
• battery indicator
• Fingerprint reader.
• Thermal management
• Webcam
• Expresscard slot (including hotplugging)
• USB (all 3 ports)
• bluetooth
• SD card slot
• LAN
• Sound (integrated speakers, integrated mic, external headphones, external mic)
• WWAN
• WLAN slot USB

Not tested:

• Windows (through GRUB-as-payload loading SeaBIOS image from disk; you have to use extracted VGA blob, dumped from memory isn't good enough)
• Thinklight.
• dock
• msata
• displayport (probably works)

proprietary components status

• CPU Microcode
• VGA option rom (optional): you need it if you wantgraphics in SeaBIOS but most payloads should work without it (text mode or corebootfb mode)
• ME(Management Engine) => you do not have to touch it(just leave it where it is)
• EC(Embedded Controller) => you do not have to touch it(just leave it where it is)

Flashing

X220 has 1 flash chip of 8M. It's subdivided in roughly in 3 parts:

• Descriptor (12K)
• ME firmware (5M-12K)
• System flash (7M)

ME firmware is not readable. Vendor firmware locks the flash and so you need to flash externally (unless until someone figures out a way around it).

• File:X220.jpg
• File:X220 chip.jpg
• 

Proceeds as follows:

• Turn off your laptop, remove battery and AC adapter.
• Remove the keyboard.
• Connect your external SPI flasher to the top SPI chip which is under palm resting space, on left side of the board. It's a 8M chip.

I recommend using SOIC clip. Depending on the flasher you use, you may have to use separate 3.3V source. Make sure not to feed more than 3.3V ot the chip. I used buspirate as flasher and 3.3V power lines from another computer.

• Read the flash. Twice. Compare the files to be sure. Save a copy of it on

external media.

flashrom -p <yourprogrammer> -r flash.bin
flashrom -p <yourprogrammer> -r flash2.bin
diff flash.bin flash2.bin

If they don't match, do not proceed.

• Recover descriptor and me firmare:

 dd if=flash.bin of=coreboot/3rdparty/mainboard/lenovo/x220/descriptor.bin \
   count=12288 bs=1M iflag=count_bytes
 dd if=flash.bin of=coreboot/3rdparty/mainboard/lenovo/x220/me.bin \
   skip=12288 count=5230592 bs=1M iflag=count_bytes,skip_bytes

• Compile coreboot
• Flash the resulting build/coreboot.rom

If you have trouble reading the chip successfully, the most common problems are

• insufficient power supply
• bad contacts
• too long wires
• bad pinout

The cable shipped with buspirate was too long, and needed to be trimmed.

See also In-System Programming