4deus Mod is a modular Decky Loader plugin for Steam Deck fixes and
customizations.
Install the latest release directly from Decky Loader using the Getting Started guide.
- Keeps the Steam keyboard above application windows when opened with a controller shortcut.
- Optionally keeps the keyboard open after pressing Enter.
- Adds a controller-friendly system-key layer with Ctrl, Alt, Fn, Esc, Delete, and F1-F12.
- Can send Alt+Shift, Ctrl+Shift, or Cmd+Space from Steam's language key while the system layer is active. Hold the key to choose a chord or Steam's native behavior directly on four keyboard keys using either trackpad; the choice is saved.
- Turns Steam's language key into Start while Fn is active.
- Optionally maps View, L1, R1, L4, R4, L5, or R5 to common typing keys while the virtual keyboard is open.
- Supports holding Ctrl, Alt, and Shift on separate Deck buttons for chords such as Ctrl+Shift+W with an on-screen letter.
- Supports sequential on-screen modifier chords: tap Ctrl, then hold Shift or Alt to latch both modifiers before pressing the final key; a short second modifier press sends the modifier-only chord immediately.
- Supports optional custom one-button quick chords such as
Ctrl+Shift+Deleteand an optional second hotkey set while R4 is held; the active set is shown on the space bar. - Matches secondary and system-key labels to Steam keyboard theme states.
- Sends system chords such as Alt+Tab, Alt+Shift, and Ctrl+Shift.
- Sends system keys through a dedicated Linux
uinputkeyboard so they reach the focused application. - Supports holding the Steam items key to switch the system layer on or off.
- Shows letters from a second enabled Steam keyboard layout on each key.
- Shows the secondary layout's symbols while Shift is active.
- Keeps secondary letters synchronized with Shift and Caps Lock.
- Supports automatic secondary-layout selection and a manually preferred layout.
- Reads layouts directly from Steam, so labels follow the layouts configured in Steam settings.
- Localizes plugin settings for every language currently supported by Steam.
- Provides optional keyboard diagnostics in the Decky plugin log.
Secondary labels are visual only. Steam remains responsible for the active layout and text input.
- Scans installed Flatpak and desktop applications without modifying Steam's shortcut database directly.
- Adds or repairs non-Steam shortcuts through Steam's live shortcut API.
- Uses one autonomous launcher with saved per-application compatibility profiles, so shortcuts continue to work when Decky is not loaded.
- Supports optional process tracking, Steam preload cleanup, Gamescope/X11 environment variables, custom working directories, arguments, and compatibility library paths.
- Includes a quick Add / Fix Parsec action that keeps the Steam session active for Parsec's real background process.
- Includes a quick Add / Fix RustDesk action with Steam runtime cleanup, RustDesk compatibility libraries, the Gamescope/X11 environment, and automatic installation of the Nested Desktop pointer hook.
- Runs the unpacked Arch Linux RustDesk package against the active Nested Desktop runtime. The unsupported Flatpak package is detected and rejected so Steam cannot launch the wrong build or enable incompatible RustDesk fixes.
- Updates existing shortcuts in place to preserve their Steam app ID, controller layout, and play history.
- Refreshes branded portrait, grid, hero, and logo artwork for Parsec and RustDesk whenever their Add / Fix actions run.
- Provides explicit install, repair, status, and removal actions for the narrowly scoped MangoHud Nested Desktop compatibility fix.
- Keeps the built-in Gamescope performance overlay running when protected KWin
processes prevent MangoApp from enumerating
/proc/<pid>/fdor/proc/<pid>/fdinfo. - Installs only a user-level systemd drop-in and a dedicated preload library; it does not replace the system MangoHud package or add runtime dependencies.
- Removes only files marked as managed by 4deus Mod and cleans the fix up when the plugin is uninstalled.
- Adds or repairs a Steam Os non-Steam shortcut for the built-in Nested Desktop, using a persistent launcher with the correct locale and IBus environment.
- Updates an existing SteamOS shortcut in place to preserve its app ID, controller layout, and play history.
- Refreshes all four Steam artwork slots from the bundled branded SteamOS artwork whenever Add / Repair runs.
- Shows a red warning and forces all RustDesk-specific switches off while the unsupported RustDesk Flatpak package is installed.
- Restores right-trackpad and right-stick cursor control, configurable clicks, and left-pad scrolling in Nested Desktop while another Game Mode application is running.
- Restores the Steam Deck touchscreen in Nested Desktop, including swipes and multiple simultaneous contacts. Touch forwarding has its own saved switch and is active only while Nested Desktop owns input focus.
- Optionally extends a fast, straight, single-finger swipe with time-based kinetic motion and a smooth fade. Taps, holds, direction changes, slow drags, multitouch, new contacts, and focus loss cancel or suppress it.
- Keeps guarded touchscreen inertia tuning behind the module's Advanced switch, with safe ranges, an explicit Apply action, and one-click defaults.
- Fixes RustDesk's duplicate cursor, click offset, and pointer teleportation by relaying only its pointer events through Nested Desktop's EIS input. The setting is enabled by default and can be disabled without restarting RustDesk.
- Provides configurable controller bindings that are sent directly to Nested Desktop while it owns focus, including when a parallel game retains Steam Input.
- Starts with Steam's Desktop Configuration: A/Enter, B/Escape, X/keyboard, Y/Space, D-pad and left-stick arrows, View/Escape, Menu/Tab, L1/Ctrl, R1/Alt, L2/right click, R2/left click, R3/left click, L4/Shift, R4/Page Up, L5/Meta, R5/Page Down, and trackpad clicks.
- Lets every binding be reassigned or cleared, provides a master binding switch, and can reset the complete set to Steam defaults.
- Activates the input bridge only while Nested Desktop is frontmost, with configurable cursor and scroll inertia that is saved between sessions.
- Uses Decky's root process only to open the protected physical touchscreen and for managed systemd compatibility drop-ins. The descriptor is passed to the latency-sensitive Nested Desktop input worker, which still runs as the regular Steam Deck user and never grabs the touchscreen away from Steam.
Remote desktop clients such as Parsec and RustDesk can forward keyboard positions or scan codes while the local or remote operating system applies the active language layout. In that setup, the Steam keyboard may display English keys even though the target system is typing Russian.
Switching Steam's own on-screen keyboard to Russian is not a reliable
workaround inside Gamescope or Nested Desktop. Users have reported a failure
where every letter produces 1 while number keys continue to work. RustDesk
also documents the distinction between position-based Map 1:1 input and
character-oriented Translate input.
4deus Mod returns Steam to its built-in QWERTY layout when a configured system language shortcut is used, and adds the secondary layout as visual labels. The remote or desktop system remains responsible for language switching, while every key shows the character that the active secondary layout will produce.
The Quick Access panel has a permanent module manager plus one tab per enabled module. Steam's native tab navigation lets L2/R2 move between them. Disabling a module removes its tab, stops its runtime work, and preserves the configured feature values for the next activation. Each enabled module tab starts with a localized Settings button, followed by its frequent, safe controls. The button opens a short, focused full-screen settings route for that module.
corepack enable pnpm
pnpm install
pnpm check
pnpm buildSee Backend architecture for the Python module boundaries and stable Decky/worker entrypoints.
Enable Keyboard diagnostics in the keyboard settings to write state,
refresh, and mutation counters to Decky's 4deusMod log every five seconds.
The option is disabled by default and resets to off whenever the plugin
restarts.
Set the matching version in package.json, commit it, and push a v* tag.
GitHub Actions verifies the tag, runs all checks, builds 4deusMod.zip,
generates a SHA-256 checksum, and publishes both files in a GitHub Release.
MIT