coreboot

coreboot™: fast, flexible and reproducible Open Source firmware!

Reproducible Coreboot

Reproducible builds enable anyone to reproduce bit by bit identical binary packages from a given source, so that anyone can verify that a given binary derived from the source it was said to be derived. There is more information about reproducible builds on the Debian wiki and on https://reproducible-builds.org. These pages explain in more depth why this is useful, what common issues exist and which workarounds and solutions are known.

Reproducible Coreboot is an effort to apply this to coreboot. Thus each coreboot.rom is build twice (without payloads), with a few variations added and then those two ROMs are compared using diffoscope. Please note that the toolchain is not varied at all as the rebuild happens on exactly the same system. More variations are expected to be seen in the wild.

There is a weekly run jenkins job to test the master branch of coreboot.git. The jenkins job is running reproducible_coreboot.sh in a Debian environment and this script is solely responsible for creating this page. Feel invited to join #reproducible-builds (on irc.oftc.net) to request job runs whenever sensible. Patches and other feedback are very much appreciated - if you want to help, please start by looking at the ToDo list for coreboot, you might find something easy to contribute.
Thanks to IONOS for donating the virtual machines this is running on!

126 (100.0%) out of 126 built coreboot images were reproducible in our test setup ! These tests were last run on 2025-01-20 for version 24.08-1239-g8d4a8c5045 using diffoscope 285.

variationfirst buildsecond build
hostname osuosl1-amd64 or osuosl2-amd64the other one
domainname is not yet varied between rebuilds of coreboot.
env CAPTURE_ENVIRONMENTnot setCAPTURE_ENVIRONMENT="I capture the environment"
env TZTZ="/usr/share/zoneinfo/Etc/GMT+12"TZ="/usr/share/zoneinfo/Etc/GMT-14"
env LANGLANG="en_GB.UTF-8"LANG="et_EE.UTF-8"
env LC_ALLnot setLC_ALL="et_EE.UTF-8"
env PATHPATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:"PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path"
env USER is not yet varied between rebuilds of coreboot.
uid is not yet varied between rebuilds of coreboot.
gid is not yet varied between rebuilds of coreboot.
UTS namespace is not yet varied between rebuilds of coreboot.
kernel version, modified using /usr/bin/linux64 --uname-2.6Linux 6.11.10+bpo-amd64Linux 2.6.71+bpo-amd64
umask00220002
CPU type AMD Opteron(tm) Processor 4284same for both builds
/bin/sh is not yet varied between rebuilds of coreboot.
year, month, datetoday (2025-01-20)same for both builds (currently, work in progress)
hour, minutehour and minute will probably vary between two builds...the future system actually runs 398 days, 6 hours and 23 minutes ahead...
Filesystemtmpfssame for both builds (currently, this could be varied using disorderfs)
everything else...is likely the same. There will be more variations in the wild.

commit 8d4a8c50452fbb2e4402464ef9f2cce0af26f6d3
Author: Mario Scheithauer 
Date:   Wed Jan 8 08:33:32 2025 +0100

    mb/siemens/mc_ehl{2...5}: Fix return in variant_mainboard_final()
    
    If no resource is found for a device, do not return directly, otherwise
    the following code will no longer be executed.
    
    Change-Id: Ida8019c383df4be2d37a1532a1759086e86124e6
    Signed-off-by: Mario Scheithauer 
    Reviewed-on: https://review.coreboot.org/c/coreboot/+/85891
    Reviewed-by: Uwe Poeche 
    Tested-by: build bot (Jenkins) 
    Reviewed-by: Werner Zeh      

cross toolchain sourcesha256sum
acpica-unix-20241212.tar.gz 9dca83cfee390b710485fbdf787048370049c05723b10cc220cfef6e13c31961
binutils-2.43.1.tar.xz 13f74202a3c4c51118b797a39ea4200d3f6cfbe224da6d1d95bb938480132dfd
gcc-14.2.0.tar.xz a7b39bc69cbf9e25826c5a60ab26477001f7c08d85cec04bc0e29cabed6f3cc9
gmp-6.3.0.tar.xz a3c2b80201b89e68616f4ad30bc66aee4927c3ce50e33929ca819d5c43538898
mpc-1.3.1.tar.gz ab642492f5cf882b74aa0cb730cd410a81edcdbec895183ce930e706c1c759b8
mpfr-4.2.1.tar.xz 277807353a6726978996945af13e52829e3abd7a9a5b7fb2793894e18f1fcbb2
Debian 12.9 package on amd64installed version
gcc 4:12.2.0-3
g++ 4:12.2.0-3
make 4.3-4.1
cmake 3.25.1-1
flex 2.6.4-8.2
bison 2:3.8.2+dfsg-1+b1
pkg-config 1.8.1-1