docs: README, TECHNICAL and TROUBLESHOOTING for 2.9.0: Steam's System settings, serial number and Wi-Fi backend, --defaults --list, the Steamify ISO

CHANGELOG.md

@@ -8,6 +8,7 @@ one per merged pull request.
 ## 2.9.0 - 2026-09-28
 
 - `d30d505` **chore: Version 2.9.0**
+- **docs: README, TECHNICAL and TROUBLESHOOTING for 2.9.0: Steam's System settings, serial number and Wi-Fi backend, --defaults --list, the Steamify ISO**
 - `a72d848` **feat: Steam's OS Version is the SteamOS release Steamify follows (steamos-3.9), its OS Codename steam-machine; About this System keeps "CachyOS Linux" (UseOSReleaseVersion)**
 - `27a4070` **fix: Steam's OS Variant shows Steamify's version (VARIANT_ID=steamify-2.9.0; Steam shows VARIANT_ID, not VARIANT)**
 - `44bfe07` **fix: No VERSION_ID in os-release: About this System said "CachyOS Linux 2.9.0"; the version is in VARIANT ("Steamify 2.9.0")**

README.md

@@ -19,6 +19,10 @@ Steam Machine.
    on the desktop too.
    - **Boot into: gamescope / desktop** - where the PC starts. Gaming mode is
      the default.
+   - Steam's **System** settings show the SteamOS release Steamify follows
+     as OS Version (e.g. `steamos-3.9`), `steam-machine` as OS Codename and
+     Steamify's version as OS Variant. The OS name stays CachyOS
+     ([details](TECHNICAL.md#what-steams-system-settings-show)).
 2. **SteamOS theme** - the Vapor look of SteamOS for the desktop, with
    **Add to Steam** in right-click menus
    ([details](TECHNICAL.md#steamos-desktop-look)).
@@ -62,7 +66,8 @@ What Steamify can do on a Valve Steam Machine:
   ([details](TECHNICAL.md#hdmi-cec)).
 - **Steam Machine support** - the front **LED bar** works, Steam's
   **hardware settings** (fan, performance) work, and the power button puts
-  it to sleep like a console.
+  it to sleep like a console. Steam's System settings show the serial
+  number, and Steam's **Wi-Fi backend** setting works.
   - **Power-off fix** - on by default: shutting down really turns the Steam
     Machine off, also with the newest CachyOS kernel
     ([details](TECHNICAL.md#power-off-fix-steam-machine)).
@@ -83,6 +88,11 @@ Open **Konsole** on your Plasma desktop and run:
 curl -fsSL https://github.com/theupriser/steamify-cachyos/releases/latest/download/steamify.sh | bash
 ```
 
+Installing CachyOS on a Steam Machine? The
+[Steamify CachyOS ISO](https://github.com/theupriser/steammachine-cachyos-live-iso)
+has Steamify built into the installer: pick the options there, and the
+first boot is already set up.
+
 Prefer to look at the script first? Clone the repository and run
 [`./steamify.sh`](steamify.sh) (keep the whole folder: it needs
 [`lib/`](lib/)).

TECHNICAL.md

@@ -111,6 +111,9 @@ Turning it off restores `/etc/plasmalogin.conf` from its backup, removes the
 SDDM autologin, sync bridge, shortcut, sudoers rule and Steam autostart, and
 switches back to plasma-login-manager.
 
+The conversion also sets what Steam's System settings show, see
+[below](#what-steams-system-settings-show).
+
 **Steam Deck/Machine icons:** `STEAM_GAMEPADUI_ARGS="-gamepadui -steamos3"`
 in `~/.config/environment.d/` (and gamescope-session's own environment
 file), which makes Steam show Steam Deck button glyphs in gaming mode.
@@ -139,6 +142,33 @@ taken from the newest `steamdeck-kde-presets` on Valve's SteamOS mirror
 Turning it off restores your previous look and panel layout, and removes `cachyos-vapor` again
 if the wizard installed it (and nothing else, like `cachyos-handheld`, needs it).
 
+## What Steam's System settings show
+
+With the SteamOS conversion on, `/etc/os-release` gets:
+
+| Key | Value | Shown in Steam as |
+|---|---|---|
+| `VERSION_ID` | `steamos-3.9`: the newest SteamOS release in Valve's repo (offline: the previous value) | OS Version |
+| `VERSION_CODENAME` | `steam-machine` | OS Codename |
+| `VARIANT` / `VARIANT_ID` | `Steamify 2.9.0` / `steamify-2.9.0` | OS Variant (`VARIANT_ID`) |
+
+The OS name stays CachyOS everywhere: Steam's OS Name comes from
+`lsb_release -d`, which isn't touched, and `NAME`/`PRETTY_NAME` stay
+CachyOS's. limine-snapper-sync finds the boot entries by that name, so
+changing it would break snapshot boot entries; `/etc/default/limine` gets
+`TARGET_OS_NAME="CachyOS"` as a guard when it has none.
+
+KDE's About this System would show `VERSION_ID` after the name
+("CachyOS Linux steamos-3.9"); `UseOSReleaseVersion=true` in
+`~/.config/kcm-about-distrorc` makes it show `VERSION`, which CachyOS doesn't
+have, so it keeps saying "CachyOS Linux".
+
+CachyOS's own hooks (`cachyos-hooks`) reset os-release on updates of
+`filesystem`; the pacman hook `zz-steamify-os-release` runs after them and
+sets the keys again (`/usr/local/libexec/steamify-os-release`). The values are
+refreshed after every Steamify run that changes something. Turning the
+conversion off removes the hook and runs CachyOS's `cachyos-branding` again.
+
 ## Front LED bar (Steam Machine)
 
 The **Steam Machine support** component, only shown on Fremont hardware
@@ -156,7 +186,14 @@ The **Steam Machine support** component, only shown on Fremont hardware
 - installs and enables `steamos-manager`, the service Steam in gaming mode
   uses for hardware settings (fan, performance, and the HDMI-CEC settings
   when [HDMI-CEC](#hdmi-cec) is on); it recognises the Steam Machine from its
-  DMI data.
+  DMI data;
+- makes the serial number readable for Steam, which shows it in its System
+  settings (`/etc/tmpfiles.d/steamify-serial.conf`: `product_serial` is
+  root-only by default);
+- makes Steam's Wi-Fi backend setting work: steamos-manager switches it in
+  `/etc/NetworkManager/conf.d/99-valve-wifi-backend.conf`, which is created
+  with `wifi.backend=wpa_supplicant` (NetworkManager's default) when no
+  backend is set anywhere yet.
 
 Turning it off removes all of that again (the AUR helper is kept).
 
@@ -433,6 +470,7 @@ For an installer (the Steam Machine ISO), without a session or prompts
 ```bash
 steamify.sh --defaults                                  # what the menu would preselect
 steamify.sh --defaults --options gaming,theme,cec,machine --boot desktop
+steamify.sh --defaults --list                           # what --defaults can set up here, as JSON
 ```
 
 `--options` turns on exactly the listed items (the menu's ids: `gaming`,

TROUBLESHOOTING.md

@@ -18,6 +18,14 @@ restarted right away (`Relogin=true`), which is why it can loop.
 Run the wizard again and press `a` in the menu to re-apply everything that's
 on (also useful after a CachyOS update). To undo a part, untick it.
 
+## "Target OS name ... not found in /boot/limine.conf"
+
+limine-snapper-sync finds the boot entries by the OS name. Steamify never
+changes that name (it only adds version keys to `/etc/os-release`), and pins
+`TARGET_OS_NAME="CachyOS"` in `/etc/default/limine`. If you see this message,
+check that `PRETTY_NAME` in `/etc/os-release` still says `CachyOS`, or set
+`TARGET_OS_NAME` in `/etc/default/limine` to the name your boot entries use.
+
 ## The LED bar on the Steam Machine stays dark
 
 Restart once more; a freshly installed driver often needs a reboot. The menu