Installing ArchLinux packages on the Steam Deck

Steam Deck's Desktop Mode allows us to tweak with the whole system, including system packages. But first, we need to be able to run sudo commands, which you can do by following this guide to set a password for your Steam Deck user.

Some stuff you should know before you start...

Can we install ArchLinux packages on the Steam Deck?

Yes, but it's not the recommended way to do it. Steam Deck's mode, while powerful, has some quirks that make this approach not the best one.

Why is it not the recommended way to install packages on the Steam Deck?

Steam OS will automatically wipe the system partition after every update. They do this to make sure that your console never breaks with new versions of the operating system.

What's the best way to install packages on the Steam Deck?

Flatpak is the best way to install packages on the Steam Deck, using the Discover app. But there are some things that don't work with Flatpak, hence the need for installing system packages on the Steam Deck.

Setting up the Steam Deck's system

NOTE: This will get undone after each system update! I recommend you to create a script to do all of this for you and run it after every update.

The first thing we need to do is make the Steam Deck's system partition writable. And there's an official command for that:

sudo steamos-readonly disable

Initialize pacman's keyring:

sudo pacman-key --init

Populate pacman's keyring with the default Arch Linux keys:

sudo pacman-key --populate archlinux

Update & upgrade the system packages:

sudo pacman -Syu