Maintaining libreboot

This section relates to maintaining libreboot. Work-in-progress

Do not follow anything here to the letter; is it only a guide representing how libreboot is maintained (for reference). This will be added to frequently from now on.

This section of the documentation applies mainly to the development version of libreboot, which is hosted in a git repository. It is not intended for the release versions of libreboot.

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Overview

The way the libreboot project is run is very similar to how a GNU/Linux distribution project is run (but for the boot firmware, not your operating system).

This page demonstrates on a high level how libreboot is maintained, how the project is run, how everything goes together, etc. For a more detailed guide, refer to each subsection for the various components/modules used in libreboot.

TODO: write this section

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Updating coreboot-libre

Coreboot-libre is the name of the deblobbed coreboot sources used in libreboot. It is also the name of the collection of scripts used for deblobbing coreboot, on each new update.

This section shows an example of how to update (re-base) to the latest version of coreboot, how to update the deblobbing scripts, and so on. This does not teach you how to change what custom patches are used, nor does it tell you how to add new boards to libreboot. It assumes that you simply want to re-base to the latest version (for instance, there could be bug fixes that you want). For those things not listed in this section, you can refer to other sections on this page instead.

Open these files in your editor (you will most likely be editing them):

If you already had a coreboot/ directory in your libreboot tree, delete it:
$ rm -rf coreboot/

Firstly, download coreboot. Do not use ./download coreboot for this, just clone coreboot, as it does in that script, like so:
$ git clone http://review.coreboot.org/coreboot

$ cd coreboot/
Get the ID of the latest commit in this clone, by reading the commit ID using e.g.:
$ git log
In resources/scripts/helpers/download/coreboot you will find a line that says git reset --hard and then a commit ID next to it. Replace this with the commit ID of the latest commit from the coreboot version that you just downloaded.

Delete the .git* resources. For example:
$ rm -rf .git*
...this is to avoid the deblobbing script from picking up files in there as blobs, which would be only false positives and increase the amount of time taken. Now come out of coreboot:
$ cd ../

Check all coreboot file names/paths in deblob; if any of them no longer exist at that name/path in the coreboot tree that you downloaded, delete the reference(s) in deblob.

Check all coreboot file names/paths in nonblobs; if any of them no longer exist at that name/path in the coreboot tree that you downloaded, delete the reference in nonblobs.

Now, back in the main root directory of libreboot (git repository), run the deblob script. This is to prevent the findblobs scripts from finding the blobs that are already deleted when running the deblob script. Like so:
$ ./resources/utilities/coreboot-libre/deblob

Now search for new blobs:
$ cd resources/utilities/coreboot-libre/
$ ./findblobs
WARNING: this will take a *long* time. Be patient! What this will do is look through the coreboot source directory, looking for blobs. It will not find the blobs that you deleted before (because they no longer exist), and it will ignore any files listed in nonblobs.

Once the findblobs script has finished, check the file tocheck (from the root, this will be resources/utilities/coreboot-libre/tocheck). These are the files detected as blobs; some might be blobs, some not. The findblobs script doesn't know how to determine between blobs and non-blobs, it only knows patterns. Distinguishing between blobs and non-blobs must be performed by you, the human being.

Now come back to the main libreboot root directory (root of the git clone). If you are still in resources/utilities/coreboot-libre/ for instance, you would do something like:
$ cd ../../../

Now delete the coreboot directory:
$ rm -rf coreboot/

Download coreboot again, only this time, using the download script. The download script also applies custom patches to coreboot (see resources/scripts/helpers/download/coreboot); if they do not apply anymore, you will have to re-base them and then update resources/scripts/helpers/download/coreboot accordingly. Anyway, download coreboot like so:
$ ./download coreboot

If the custom patches no longer apply, and you have to re-base (or replace?) some patches, please do this in coreboot upstream, not in libreboot. Then re-include new patches from upstream, into libreboot. Here is coreboot's guide for contributing patches:
http://www.coreboot.org/Git.

Update all configs:
$ ./build config corebootupdate
This simply takes all of the coreboot .config files from resources/libreboot/config/ and does make oldconfig on them. It usually works. If it doesn't, you'll need to recreate those configs from scratch using make menuconfig in coreboot (see ../git/index.html#config)

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Adding a new board to libreboot

TODO: write this section

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Add/remove/modify patches in coreboot-libre

TODO: write this section

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Updating GRUB

TODO: write this section

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Add/remove/modify patches in GRUB

TODO: write this section

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Change how the GRUB payload (grub.elf) is built (utility: grub-assemble)

TODO: write this section

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Modify the configuration used in GRUB

TODO: write this section

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Updating flashrom

TODO: write this section

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Add/remove/modify patches in flashrom

TODO: write this section

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Updating bucts

TODO: write this section

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Add/remove/modify patches in bucts

TODO: write this section

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Updating MemTest86+

TODO: write this section

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Add/remove/modify patches in MemTest86+

TODO: write this section

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Copyright © 2015 Francis Rowe <info@gluglug.org.uk>
This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. A copy of the license can be found at ../license.txt.

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information.