# ThinkPad T400

It is believed that all or most T400 laptops are compatible. See notes about CPU compatibility for potential incompatibilities.

There are two possible flash chip sizes for the T400: 4MiB (32Mbit) or 8MiB (64Mbit). This can be identified by the type of flash chip below the palmrest: 4MiB is SOIC-8, 8MiB is SOIC-16.

The T400 laptops come with the ME (and sometimes AMT in addition) before flashing libreboot. Libreboot disables and removes it by using a modified descriptor: see gm45_remove_me.html (contains notes, plus instructions)

Flashing instructions can be found at ../install/index.html#flashrom

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The T400 is almost identical to the X200, code-wise. See x200.html.

## Hardware register dumps

The coreboot wiki shows how to collect various logs useful in porting to new boards. Following are outputs from the T400:

- T400 with Winbond W25X64 flash chip (8MiB, SOIC-16) and Lenovo BIOS 2.02 (EC firmware 1.01):
  - lspci output
  - lsusb output
  - superiotool output
  - inteltool output
  - ectool output
  - msrtool output, errors
  - dmidecode output
  - biosdecode output
  - nvramtool output
  - dmesg
  - flashrom probe output, errors
  - flashrom read output, errors
  - /sys/class/sound/card0/hwC0D0/init_pin_configs
  - /proc/asound/card0/codec#0
  - /proc/cpuinfo
  - t400_flashrom_read_with_bbb.txt
  - t400_flashrom_write_with_bbb.txt
- Version of flashrom used for the external flashing/reading logs is the one that libreboot git revision c164960 uses.

Copyright © 2015 Francis Rowe <info@gluglug.org.uk>
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