microcode: added arch microcode install

wiki/linux/arch-linux/arch-linux.md

@@ -2,10 +2,10 @@
 
 [Arch Linux](https://archlinux.org/) is a rolling-release, general-purpose Linux
 distribution.
-Arch Linux uses the [pacman](./pacman_and_yay.md) package manager.
+Arch Linux uses the [pacman](./package_manager.md) package manager.
 The Arch User Repositories (AUR) features community-made packages that can be
 installed with different
-[package manager that inlcude access to the AUR](/wiki/linux/arch-linux/pacman_and_yay.md).
+[package manager that inlcude access to the AUR](/wiki/linux/arch-linux/package_manager.md).
 
 ## Installation Medium
 
@@ -16,3 +16,19 @@ The ISO file can be found on the
 The iso can be written on an USB-stick using the command
 `dd bs=4M if=<path to ISO> of=/dev/sdx conv=fsync oflag=direct status=progress`.
 `<path to ISO>` points the command to the location of the ISO file
+
+## Enable Microcode Updates
+
+The microcode of Intel and AMD CPUs can be automatically updated by installing
+the `amd-ucode` or `intel-ucode` package depending on your CPU.
+The following description assumes the system is installed with
+[UEFI bootloader](/wiki/linux/arch-linux/installation.md#10-install-and-configure-uefi-bootloader)
+similar to the [recommended guide](/wiki/linux/arch-linux/installation.md).
+The microcode updates can then be enabled by adding the following line into
+`/boot/loader/entries/arch.conf`:
+
+```txt
+initrd  /<installed microcode package>.img
+```
+
+`<installed microcode package>` is either `amd-ucode` or `intel-ucode`.

wiki/linux/arch-linux/package_manager.md

@@ -9,6 +9,16 @@ In this article `yay` is used as the go to AUR manager.
 `yay` is also a wrapper for `pacman` so you can just use `yay` instead of pacman
 to install programs.
 
+## Update Mirrorlist
+
+After a while not updating the system it is possible for the mirrorlist to be
+outdated.
+This can be fixed by updating it with the following command:
+
+```sh
+curl -o /etc/pacman.d/mirrorlist https://archlinux.org/mirrorlist/all/
+```
+
 ## Bugfixes
 
 ### Error while importing keys

wiki/linux/flatpak.md

@@ -6,7 +6,7 @@ linux systems.
 ## Setup
 
 The `flatpak` package can be installed by most distribution specific package
-managers (e.g. [pacman or yay](./arch-linux/pacman_and_yay.md)).
+managers (e.g. [pacman or yay](./arch-linux/package_manager.md)).
 After installation it is important to add [flathub](https://flathub.org/home),
 a source for many Flatpak packages.
 The addition of this can be done by running

wiki/linux/microcode.md

@@ -0,0 +1,15 @@
+# Microcode
+
+Processor vendors release stability and security updates to the processor
+microcode.
+
+## Installation
+
+Most Linux based operating systems feature packages depending on the processor
+manufacturer (on Arch Linux for example `intel-ucode` and `amd-ucode`).
+
+## Automatic Updates
+
+Automatic updates can be enabled depending on bootloader and operating system.
+For Arch Linux a description is given in the
+[Arch Linux entry](/wiki/linux/arch-linux/arch-linux.md#enable-microcode-updates).

wiki/obs.md

@@ -21,8 +21,10 @@ This guide assumes it is set up according to the section in the
 [V4L2 entry](./linux/v4l2.md#v4l2loopback).
 Make sure to start and/or enable it.
 Additionally `obs-v4l2sink` needs to be installed.
-Under `Tools/v4l2sink` select the device path set up in V4L2 and the `YUV420`
-video format.
+Under `Tools/v4l2sink` select the device path set up in V4L2.
+Select the same video format as set for your camera.
+For Linux see [the webcams entry](/wiki/linux/webcams.md#configure-the-webcam)
+to configure the video format.
 Afterwards the virtual camera can be started.
 
 ### Background Removal