6.4 KiB
Well, if the files cannot be freely redistributed, then we can't provide them. So how do we handle that, in the context of Libreboot releases?
The solution
The answer is very simple: these files are NOT provided, at all! However,
the very same logic used by the build system can be run standalone, to re-insert
these vendor files on release ROMs. The inject script detects what files are
needed for your ROM image.
The script will detect what board you're inserting on, or you can manually tell it what board, and it will fetch them for you, inserting them, so that your board is ready to flash - flashing it without these required files may result in a brick.
Vendor file locations
During auto-download of files, they are saved to these locations within the Libreboot build system:
- ME firmware:
vendor/*/me.bin- the*can be any given directory. Different ones will be used by given boards, but the directory name may not match the board target name. - SMSC SCH5545 fan control firmware (for Dell T1650):
vendor/t1650/sch5545ec.bin - SMSC KBC1126 embedded controller firmware, on HP EliteBooks:
ec/ - Intel MRC firmware, used for ram/peripheral init on Haswell machines such as
thinkpad t440p/w541:
mrc/
The above list refers to the non-redistributable files, and these are not
directly included in releases. These are auto-downloaded during the build.
The me.bin files are produced by extracting them from vendor updates and
neutering them with me_cleaner so that Intel ME is disabled during early boot.
Inject vendor files into ROM
You must determine the correct board name, for your board, based on the list generated when running this command:
./build roms list
For example, t440pmrc_12mb corresponds to ThinkPad T440p with MRC firmware.
Whereas t440plibremrc_12mb corresponds to T440p with libre MRC firmware.
Another example: x230_12mb corresponds to Thinkpad X230.
In order to inject the necessary files into a rom image, run the script from the root of lbmk and point to the rom image.
If you only wish to flash a release rom then the process of injecting the necessary files is quite simple. Run the injection script pointing to the release archive you downloaded:
./vendor inject /path/to/libreboot-20230319-18-g9f76c92_t440pmrc_12mb.tar.xz
The script can automatically detect the board as long as you do not change the file name.
You can then find flash-ready ROMs in /bin/release/
Alternatively, you may patch only a single rom file, but you must supply the correct board target name as alluded to above. For example:
./vendor inject -r x230_libreboot.rom -b x230_12mb
Optionally, you can use this script to modify the mac address of the rom with the -m flag.
For example:
./vendor inject -r x230_libreboot.rom -b x230_12mb -m 00:f6:f0:40:71:fd
Check that the files were inserted
You must ensure that the files were inserted.
Some examples of how to do that in lbmk:
./update trees -b coreboot utils
Now you find cbutitls/default, which is a directory containing cbfstool
and ifdtool. Do this on your ROM image (libreboot.rom in the example
below):
./cbutils/default/cbfstool libreboot.rom print
You should check that the files were inserted in cbfs, if needed; for example, EC firmware or MRC firmware.
Next:
./cbutils/default/ifdtool -x libreboot.rom
This creates several .bin files, one of which says me in it (Intel ME).
Run hexdump on it:
hexdump flashregion_2_intel_me.bin
Check the output. If it's all 0xFF (all ones) or otherwise isn't a bunch
of code, then the Intel ME firmware wasn't inserted.
You'll note the small size of the Intel ME, e.g. 84KB on sandybridge platforms.
This is because lbmk automatically neuters it, disabling it during
early boot. This is done using me_cleaner, which lbmk imports.
Errata
NOTE: Haswell machines come with mrc.bin or without, depending on the
ROM image configuration. These ROM configs have mrc.bin: t440pmrc_12mb
and w541mrc_12mb. These ROM configs have libre MRC: t440p_12mb
and w541_12mb - it is critical that you choose the right one, when using
the -b flag in the ./vendor inject command. For example, if you
used -b t440p_12mb on a ROM image that actually corresponds
to t440pmrc_12mb, then the required mrc.bin file would not be added
and that ROM would not boot when flashed.
NOTE: the MAC changer makes use of nvmutil, which you can read more about in
the nvmutil documentation.