# Maintaining libreboot

This section relates to maintaining libreboot.

Do not follow anything here to the letter; is it only a rough guide representing how libreboot is maintained (for reference).

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.

- Overview
- Updating coreboot-libre
  - Adding a new board to libreboot
  - Add/remove/modify patches in coreboot-libre
- Updating GRUB
  - Change how the GRUB payload (grub.elf) is built (utility: grub-assemble)
  - Modify the configuration used in GRUB
  - Other maintenance-related tasks in GRUB
- Updating flashrom
- Updating bucts
- Updating MemTest86+

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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.

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# Updating coreboot-libre

NOTE: it helps to own all libreboot-compatible systems here, or have reliable (and fast) access to a team of testers.

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):

- resources/scripts/helpers/download/coreboot
- resources/scripts/helpers/build/module/coreboot
- resources/utilities/coreboot-libre/deblob
- resources/utilities/coreboot-libre/nonblobs
- resources/utilities/coreboot-libre/nonblobs_notes
- resources/scripts/helpers/build/roms/helper
- resources/scripts/helpers/build/roms/withgrub

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.

- Files in tocheck that you identify as blobs, should be added appropriately to resources/utilities/coreboot-libre/deblob
- Files in tocheck that you identify as non-blobs, should be added appropriately to resources/utilities/coreboot-libre/nonblobs - also, if you feel it necessary, add an explanation of it in resources/utilities/coreboot-libre/nonblobs_notes

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 ./build config corebootreplace (optionally add a config name), or ./build config corebootmodify (ditto) (see ../git/index.html#config)

Finally, build *all* ROM images using the instructions at ../git/index.html, to verify that everything still builds.

Once you've verified that building isn't broken, test *all* boards (you don't need to test all ROM images, only one vesafb and one txtmode image for each configuration). If you do not have all systems supported in libreboot, then you will need to get other testers for those boards.

If you have established a build issue, or a board no longer works (booting issues, bugs during/after boot, etc), you'll need to fix it upstream: http://www.coreboot.org/Git and then re-update coreboot (or apply patches from upstream).

You should also make sure to update resources/scripts/helpers/build/trim/coreboot which purges unused parts of coreboot. Basically, if it's purging parts that you now need, then that's a bug and you should fix it.

You should also test the resulting ROM images from building with the new or modified coreboot revision.

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# Adding a new board to libreboot

Make sure that the board is supported, and that the patches are included (if there are custom patches that you need). Add configs for it like so:
$ ./build config corebootreplace new_board_name_here

This can also be used for replacing an existing config.

Configure the board. Make sure to add the steps to the config section in ../git/index.html.

When you're done, the config will be stored in resources/libreboot/config/. Now build-test it and then check that it actually works.

The following scripts may also need to be modified before building: resources/scripts/helpers/build/roms/withgrub and resources/scripts/helpers/build/roms/helper

The following can be used when updating coreboot-libre:
$ ./build config corebootupdate (adding a board name on the end is optional)

The following can be used if you want to modify an existing configuration:
$ ./build config corebootmodify (adding a board name on the end is optional)

You should also make sure to update the whitelist in resources/scripts/helpers/build/trim/coreboot which purges unused parts of coreboot (including boards). Basically, if it's purging parts that you now need, then that's a bug and you should fix it.

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# Add/remove/modify patches in coreboot-libre

Under resources/scripts/helpers/download/coreboot you can find the instructions used for patching coreboot.

Modify the commit ID on the git reset --hard line accordingly, and update the list of patches used accordingly. Do not cherry-pick from review.coreboot.org directly; instead, include the diff in resources/libreboot/patch/ and use git am (you can get the diff by using git-format-patch).

When you're done, simply download coreboot again:
$ ./download coreboot

Finally, re-build the parts from coreboot that are used by the build system:
$ ./build module coreboot

Instead of running the above command, you can save time by copying out the crossgcc that you compiled before (from coreboot/util/crossgcc/) and then putting it back. After you've done that, run everything in resources/scripts/helpers/build/module/coreboot except for the part that builds GCC.

You should also test the resulting ROM images from building with the new or modified coreboot revision.

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# Updating GRUB

$ rm -Rf grub/
$ git clone git://git.savannah.gnu.org/grub.git
$ cd grub/
$ git log

Open the file resources/scripts/helpers/download/grub and replace the commit ID on the line that performs git reset --hard with the commit ID of the GRUB revision that you just downloaded.

$ cd ../
$ ./download grub

If it fails because of merge conflicts, you'll need to re-base or (as appropriate) remove the offending patch(es) in resources/scripts/helpers/download/grub.

Finally, verify that it will build:
$ ./build module grub

Since GRUB is the payload in libreboot, you should also build the ROM images and test them, with this different GRUB version that you have prepared.

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

Look in resources/utilities/grub-assemble/.

gen.sh creates ELF executables of GRUB with different configurations: text-mode or framebuffer mode in coreboot. Essentially, the text-mode version has no background nor any custom fonts, and contains MemTest86+. You probably don't need to modify these files at all.

grub_memdisk_keymap simply adds all the keyboard layout files. The keymap files are in keymap/, and can be added to using the instructions at ../grub/index.html#grub_custom_keyboard.

modules.conf defines which modules will be included in the GRUB ELF executable.

Since GRUB is the payload in libreboot, you should also build the ROM images and test them, with this different GRUB version that you have prepared.

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# Modify the configuration used in GRUB

Look in resources/scripts/helpers/build/roms/withgrub to see how the GRUB configuration files are generated.

You might need to modify this. You can also modify the default configuration by making changes to the files under resources/grub/config/

Since GRUB is the payload in libreboot, you should also build the ROM images and test them, with this different GRUB version that you have prepared.

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# Updating flashrom

Modify these files: resources/scripts/helpers/download/flashrom and resources/scripts/helpers/build/module/flashrom.

Patches are in resources/flashrom/patch/

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# Updating bucts

bucts doesn't really need updating, but the patches are in resources/bucts/patch, the download script is resources/scripts/helpers/download/bucts and the build script is resources/scripts/helpers/build/module/bucts.

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# Updating MemTest86+

MemTest86+ doesn't really need updating, but the patches are in resources/memtest86/patch, the download script is resources/scripts/helpers/download/memtest86plus and the build script is resources/scripts/helpers/build/module/memtest86plus.

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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 ../cc-by-sa-4.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 ../cc-by-sa-4.txt for more information.