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Support early microcode update directly #40
Description
Currently, early microcode updates are supported by booting the kernel with two initrds: a microcode unage followed by booster's image.
But with 3.5M, the intel-ucode.img image is quite large. When not creating a universal image, booster could create its own early image with unneeded microcode code stripped. For my system, the stripped image is just 104k in size.
This can be done by running something equivalent to this command:
bsdtar -Oxf /boot/intel-ucode.img | iucode_tool -tb --scan-system --write-earlyfw=/tmp/iucode-stripped.img -
The final booster image that's created now just has to be appended as is to create a final bootable image.
Since the AMD ucode image is just 40K, stripping shouldn't be necessary and the image can just be prepended as-is.
Activity
anatol commentedon Feb 26, 2021
I wonder if better place for such improvement would be
intel-ucodepost install hook that generates/boot/intel-ucode-stripped.imgout of/boot/intel-ucode.img.Actually the full
intel-ucode.imgdoes not have to be under/boot. It can stay at/usr/share/intel-ucode/..and the hook generates slim platform-specific/boot/intel-ucode.img.The same idea applies to AMD ucode.
anatol commentedon Feb 26, 2021
cc @eworm-de @jelly
nl6720 commentedon Mar 2, 2021
The correct place would be
/usr/lib/firmware/intel-ucode/. See FS#59841 (the rationale for that feature request is different, though).dkwo commentedon Jan 10, 2024
so, supposing microcode is at /usr/lib/firmware/intel-ucode (stripped or not), but not necessarily at /boot, how do i tell booster to append it to its initram image?
anatol commentedon Jan 10, 2024
The best way to handle the microcode is to decouple it from the initramfs completely. All modern bootloaders support loading multiple images so one image can be used for microcode, and another image comes from booster.
To generate the ucode image you can use tools like this one https://github.com/anatol/ucode-image-gen
oech3 commentedon Feb 17, 2025
extra_files: /kernel/x86/microcode/GenuineIntel.binin/etc/booster.yamland hook tobash -c 'mkdir -p /kernel/x86/microcode;iucode_tool -S /usr/lib/firmware/intel-ucode -w /kernel/x86/microcode/GenuineIntel.bin --overwrite'work. This hack leave dirty file/kernel/x86/microcode/GenuineIntel.bin.