Does sudo apt upgrade update my microcode?

Question

So the question above in more generally: does the linux updates (on ubuntu, redhat, debian, etc...) update my microcode as well? or I have to update my CPU's microcode manually?

I have the microcode package installed.

Thx for your answer.

Answer 1

Microcode is usually packaged for the distro. I've seen microcode updates in Debian based (such as Debian, Ubuntu, Mint), and Red Hat based (such as CentOS, Fedora (which is Red Hat's upstream), and Scientific Linux, as well as lesser known ones, like Oracle Linux, Amazon Linux, and CloudLinux).

TL;DR: Yes, microcode is usually updated by your package manager.

Answer 2

First of all your BIOS/UEFI may attempt to update the CPU microcode which means it can be updated by updating your firmware.

It's actually the Linux kernel itself that has the built in ability to do microcode updates so long as those updates are distributed with Linux. This is usually a package such as linux-firmware. But on some distrobutions like Arch-Linux its separated as intel-ucode. Microcode is usually not freesoftware so it will have varying support and inclusion by distributions.

ArchLinux: intel-ucode and linux-firmware

Debian and Ubuntu: amd64-microcode and intel-microcode

Fedora: microcode_ctl for intel, linux package for amd and others.

Answer 3

Sort of. Some distros/processors probably do it by default, but on others (ex. ArchLinux with Intel hardware) you need to install a seperate package intel-ucode and edit bootloader options to apply the updates.

For example for GRUB, you need to change the initrd line to:

[...]
    echo    'Loading initial ramdisk ...'
    initrd  /intel-ucode.img /initramfs-linux.img
[...]

If you have AMD hardware, it's enough to install linux-firmware package.

For more information, please see https://wiki.archlinux.org/index.php/Microcode