Installing FreeBSD 14.2 on a Steam Deck

Update: A full write-up has been posted on my blog at: https://blog.linh.social/2025/01/11/installing-running-freebsd-on-steam-deck/. The post also includes some corrections and new learnings since creating this gist.

Installing onto the internal NVMe SSD

Download and burn a FreeBSD 14.2 amd64 installer ISO from FreeBSD.org
Burn the installer ISO on to a USB drive, or use a multi-boot tool like IODD or Ventoy
Use a USB dock or hub (Anker PowerExpand or 543 6-in-1 USB hub is what I've been using) with USB power delivery pass-through to connect the following devices:
1. USB-C power adapter
2. USB keyboard
3. USB boot drive with FreeBSD installer burned or loaded on it
4. USB Ethernet adapter that has support under FreeBSD
With the Steam Deck powered off, press and hold the Volume Down button and press the Power button. Hold down the Volume Down button until the firmware boot menu appears
Select the USB device with the FreeBSD installer
In the FreeBSD installer, you need to use the USB Ethernet adapter for network access. See Notes section for more.

Installing onto a microSD Card

Download either the FreeBSD-14.2-RELEASE-amd64-ufs.raw.xz or the FreeBSD-14.2-RELEASE-amd64-zfs.raw.xz raw disk images from FreeBSD.org or a mirror
Using BalenaEtcher, Raspberry Pi Imager, or dd, burn the uncompressed raw disk image to a microSD card (32 GB or larger is recommended)
With the Steam Deck powered off, press and hold the Volume Down button and press the Power button. Hold down the Volume Down button until the firmware boot menu appears
Select the EFI SD/MMC Card device from the list
After FreeBSD has booted up, default root password is blank
The main partition should be resized upon first start up

Getting Wireless Interface Active

Wireless networking is currently not working, but included are some of the steps taken to try to get it working.

Install the wifi-firmware-rtw88-kmod-rtw8822c-20241017.1401000_1 package by running:

pkg install wifi-firmware-rtw88-kmod-rtw8822c-20241017.1401000_1

The following lines needs to be added to /boot/loader.conf

rtw88_rtw8822c_fw_bin_load="YES"
compat.linuxkpi.skb.mem_limit=1

The following lines may also need to be added to the same file, but those have not been vetted:

sysctl compat.linuxkpi.rtw88_pci_disable_aspm=1
sysctl compat.linuxkpi.rtw88_disable_lps_deep=1

In /etc/rc.conf, add the following lines to assign rtw880 to wlan0 and set the wireless country and regulatory domain (FCC US is used):

wlans_rtw880="wlan0"
create_args_wlan0="country US regdomain FCC"

Configuring the interface to use WPA Supplicant and DHCP in /etc/rc.conf:

ifconfig_wlan0="WPA SYNCDHCP"

Add the appropriate wireless network SSID and pre-shared key to /etc/wpa_suppliant.conf:

network={
    ssid "SSID"
    psk "Pre-shared Key or Passphrase"
    priority 0
}

Restart networking by running:

service netif restart
service routing restart

Installing KDE Plasma 5 and GPU Drivers

With the Steam Deck connected to the network and is able to access the Internet, run the following commands to install the AMD GPU kernel modules and drivers.

pkg install drm-kmod
sysrc kld_list+=amdgpu

It is recommended to reboot at this point to let all of the required drivers and kernel modules to load.

Installing KDE Plasma 5

To use KDE Plasma 5 with X.org and using the SDDM login manager, run the following commands:

pkg install xorg kde5 sddm firefox-esr
sysrc dbus_enable="YES"
sysrc sddm_enable="YES"

Also, add the following lines to /etc/sysctl.conf

net.local.stream.recvspace=65536
net.local.stream.sendspace=65536

KDE Plasma 5 with Wayland was not tested and will require additional work

Installing GNOME

An alternative to KDE and X.org would be GNOME and Wayland.

pkg install xorg gnome gdm firefox-esr alacritty
sysrc dbus_enable="YES"
sysrc gdm_enable="YES"