Intel microcode

Article description::This article describes the process of updating the microcode on Intel processors.

Kernel
You need to activate the following kernel options:

Software
You can now install the microcode

And a tool to manipulate it

Configuration
After emerging, generate the microcode cpio archive using :

Syslinux
multiple initrd file separate by commas, early_ucode.cpio load first

GRUB Legacy
Add the generated microcode to your kernel command line as an initrd parameter (this should be done even if you don't use an initrd image in order to boot, the microcode update merely leverages the initrd hooks):

GRUB
Change this small section of from:

To this:

Regenerate the with:

Reboot and you're all done.

systemd-boot
Add the microcode as an argument to an initrd line. If you already have an initrd line, ensure the microcode line occurs first. The path to the microcode should be absolute to the root of the ESP.

For more information, see The Boot Loader Specification.

Xen (EFI)
Add a line to your xen.cfg with the 'ucode=' option. The path to the microcode is relative to the xen.efi binary, so you will need to write the microcode into the correct location (default is /boot/EFI/Gentoo) or copy it there.

For more information, see the Xen EFI documentation.

Verification
Here is an example of a CPU with no available microcode updates or the system was not configured to load them properly:

Here is the same CPU but with microcode updates being applied successfully:

Kernel
Activate the following kernel options:

Software
Install :

OpenRC
Start microcode-ctl:

To start microcode-ctl at boot time, add it your boot runlevel:

systemd
See: Systemd. Simply make sure that the Microcode loader is set as a module in the kernel configuration as noted above. You don't need to add a service or do anything else.

Software
You can install the officially published microcode package and let it automatically processed by

And you can use this tool to identify your actual CPU signature(s)

To find the appropriate filename(s) for the listed signature(s) use:

The signature found in the microcode bundle 49, so the filename to use is intel-ucode/06-3c-03

Kernel
You need tho enable and configure the following kernel options:

Rebuild and install the kernel as normal.

Verification
After the next reboot, you should see something like this:

External resources

 * http://www.win-raid.com/t154f16-Tool-Guide-News-quot-UEFI-BIOS-Updater-quot-UBU.html - An example unofficial source for microcodes