my daily driver is the Thinkpad T400, the most powerful laptop that you can libreboot to remove completely the proprietary Lenovo BIOS in favor of a fully open source BIOS. The distro on it its Parabola GNU/Linux-libre: a 100% free distribution.\
I have done a series of mods on this machine, and more are to come. What follows is a list of some useful resources on the T400 itself and the mods compatible with this device.
The Libreboot project provides free, open source (libre) boot firmware based on coreboot, replacing proprietary BIOS/UEFI firmware. I made a guide on how to do that. It's [here](https://bytemeifyoucan.lol/p/my-t400-libreboot-guide/).\
The Official Libreboot site is [this](https://libreboot.org/). The Thinkpad T400 official page is [this](https://libreboot.org/docs/hardware/t400.html).
It is possible to install a series of quad-core processors on the T400, taking advantage of the fact that they have the same socket of the dual-core Core Duos that come with stock machine.\
You will need some soldering skills and decent amount of patience. A very well done guide can be found [here](https://thonkpeasant.xyz/guides/other/quad.html).\
The original post can be found [here](https://thinkpad-forum.de/threads/core2-quad-mit-coreboot-libreboot-auf-t500-wahrsch-auch-t400-benutzen-beta.199129/). (in german)
Cooling mods really do exists out there, even tho I have never tried one on my T400s, considering i have heard mixed opinions about the actual improvements when it comes to the CPU degrees. Mileage may vary.\
All guides follow more or less the same principle: remove the metal sheeting from the plastic bottom casing and drill holes in the case. Examples of the procedures are [this](https://thonkpeasant.xyz/guides/other/cool.html) and [this](https://www.instructables.com/Fix-a-Thinkpad-T400s-Thermal-Issues-Once-and-For-/).
I am currently working on a variation of a mod I have seen floating around the world wide web. It's [this one](https://hackaday.com/tag/thinkpad-ultrabay/). In the article the laptop used is the T420 so I changing the 3D printed part to fit the T400 ultrabay.\
More info and **maybe** a guide will appear in the future, depending on how much time and effor i want to waste on this idea.
The T400 Express Card slot allows you to slot in any compatible Express Card 54, i think the most used card is the one that gives you one or two (depending on the model) USB 3.0 plugs, with up to (i think) 5Gbps transfer speed. Cool shit.
The distro i use on my librebooted T400 is Parabola GNU/Linux-libre, a community-driven, "labour-of-love" effort to maintain a 100% free (as in: freedom) operating system distribution that is lean, clean, and hackable.\
I made a guide on the manual installation of Parabola with an encrypted setup and Open-RC [here](https://bytemeifyoucan.lol/p/parabola-installation-guide/).
