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remove redundant information 

it is already mentioned in the policy page, and
freedom states page. it doesn't belong in the build
instructions, where the user is only interested in
building libreboot.

politics and tech should be separate, even if the
libreboot project is very political in general.

Signed-off-by: Leah Rowe <info@minifree.org>
master
Leah Rowe 2024-02-21 21:07:44 +00:00
parent 197ed1bab4
commit 62b45c4eb6
1 changed files with 0 additions and 118 deletions
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site/docs/build/index.md vendored
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@ -181,121 +181,3 @@ example want to modify a config, e.g.:
Or perhaps add a new board! The maintenance manual will teach you how the
Libreboot build system (lbmk) works!
Post-compilation steps
======================
So you compiled your Libreboot image? Congratulations!
Before you flash, please make sure that you *dumped* two copies of the original
firmware just in case (verifying the hashes of each dump, to ensure that they
match), using the `-r` option in flashprog.
NOTE: Libreboot standardises on [flashprog](https://flashprog.org/wiki/Flashprog)
now, as of 27 January 2024, which is a fork of flashrom.
There are some additional considerations:
Regarding binary blobs
----------------------
Firstly, you should read the Libreboot *Binary Blob Reduction Policy*:
<https://libreboot.org/news/policy.html>
A lot of mainboards in Libreboot will boot entirely with free software,
but there are certain newer mainboards supported in Libreboot
that need binary blobs added to them, mostly for minor initialisation tasks.
They are *automatically* inserted during the build process, but then deleted
during the *release* process; images built directly from lbmk can be flashed
without further modification, but release images need to have these files
re-inserted (e.g. KBC1126 EC firmware on HP EliteBooks). Please read this page
for context:
<https://libreboot.org/docs/install/ivy_has_common.html>
The scripts under directory `script/vendor/` are the ones that do this.
Specifically, `script/vendor/download`. The benefit of this is that you
do not need to extract anything from the original vendor image (e.g. Lenovo
UEFI image).
To know if this was performed on your board, you can read the Freedom Status
page which documents which files are used (if any), on which boards:
<https://libreboot.org/freedom-status.html>
There are specific files that you must know about, so they will be covered
next:
### Regarding CPU microcode
Libreboot release archives provide ROMs with or without CPU microcode updates,
but the newest revisions of lbmk (from `lbmk.git`) *only* build ROM images that
contain microcode updates, by default. Libreboot's build system contains a script
that will generate release archives, and this is used to provide Libreboot
releases; this script is what provides the images with microcode removed,
alongside the default ones generated by lbmk during the build.
Please read:
<https://libreboot.org/freedom-status.html#cpu-microcode>
The linked page has info, and includes instructions about how to manually remove
them, if you wish to do so. Removal of CPU microcode updates (on Intel/AMD
processors) will result in unpredictable security/stability issues, so beware.
Further context is provided in the Libreboot *Binary Blob Reduction Policy*:
<https://libreboot.org/news/policy.html>
We *recommend* that you do not delete these updates, but you have the freedom
to choose. Additionally: we have only tested certain mainboards under this
configuration. To know which ones they are, do this in `lbmk.git`:
cd config/coreboot/
git grep microcode_required
Example entry:
e6400_4mb/target.cfg:microcode_required="n"
If it says `="n"`, that means it has been tested. That *does not* mean it will
be stable, it's just that we're reasonably sure it will at least *boot* most
of the time, but you should expect random instability e.g. kernel panics.
If a given mainboard *excludes* `microcode_required` in `target.cfg`, or if
it says `microcode_required="y"`, then the release ROMs will only contain
microcode updates. Manual removal (as above) is still possible, but it has
not been tested and is not recommended.
NOTE: ARM-based chromebooks (that Libreboot supports) don't use microcode at
all. This section is only revelant for x86 (Intel/AMD).
### Regarding Nvidia GPU ROM (Dell Latitude E6400)
Dell Latitude E6400 comes in two variants: Nvidia graphics, or Intel graphics.
More information is available on the page:
<https://libreboot.org/docs/hardware/e6400.html>
The intel graphics model can boot with coreboot's native video initialisation,
which is free software. The *Nvidia* model (comes with Nvidia GPU) requires
proprietary code called a *VGA Option ROM* to initialise the video display in
early boot.
Libreboot automatically fetches this during the build process, inserting it into
the very same ROM image that can be flashed on either model, but the VGA ROM
will only be *executed* if you actually have the Nvidia *GPU* on your board.
**ALSO: Libreboot 20230625 did not support Nvidia models at all (only Intel).
In releases, only Libreboot 20231021 and newer will support it.**
Pre-built ROM images from release archives since 20231021 will *not* contain
this file by default, but it will be present if you compiled directly from lbmk.
To remove it, do this:
./cbutils/default/cbfstool libreboot.rom remove -n pci10de,06eb.rom
The cbfstool binary was compiled when your image (target `e6400_4mb`) was
compiled, which can alter the file system within your coreboot image.
Obviously, removing this VGA ROM will mean that the ROM image will only work
correctly on Intel GPU variants of E6400, but you probably knew that already!
(If you're using a release archive instead, you can re-insert the VGA ROM by
following [these instructions](../install/ivy_has_common.md))