System variable detection causing game confusion

Evil1nside · July 17, 2026, 6:34am

Hello good people on the internet.
As some of you already know, there has been an issue with the set of available resolution options in the game settings when playing on Linux.
The workaround for this issue was to simply use a launch option argument before starting the game(SteamDeck=0) which works alright for most systems, but there are still some that doesn’t receive the same treatment.

It seems like, apart from the SteamDeck variable detection, there’s an additional check being made by the game’s code.

The same issue happened on a brand new Steam Machine with SteamOS 3.8.
A user on Git was able to fix the issue by doing some claude coding. It basically edits some device metadata file in the il2cpp_data/ folder of the No Rest for the Wicked game. IL2CPP looks like some backend used by Unity, and in this particular case, used by the game’s runtime to detect the device model via a SystemInfo lib (?)
Both Steam deck and Steam Machine have names with (Valve) in them, which triggers the custom detection code in the game’s runtime to force handheld resolutions in the graphics options, which is wrong, and should not happen.

Proof that the issue was fixed after the above edits:

Here’s an AI generated summary of the root cause and how to fix it :

Environment

Hardware: Valve Steam Machine (Fremont, HawkPoint APU), SteamOS 3.8.x, Desktop Mode
Game: No Rest for the Wicked (appid 1371980), Unity 6000.1.15 IL2CPP, Proton
SystemInfo.deviceModel = Fremont (Valve)

Root cause

The IL2CPP metadata contains the handheld-detection fields:
s_deviceModelContainsValve
s_deviceModelContainsRogAlly
s_processorIsSteamDeckOledModel
IsRunningOnHandheld / RunningOnSteamDeck / m_isSteamDeck

and the comparison string literal is (Valve) (7 chars). The check is effectively:
s_deviceModelContainsValve = SystemInfo.deviceModel.Contains("(Valve)");

Steam Deck reports Jupiter (Valve) / Galileo (Valve)
Steam Machine reports Fremont (Valve)

All contain the (Valve) suffix, so the Steam Machine is misclassified as a handheld.

The game then re-applies handheld graphics defaults at runtime, overwriting any user setting (confirmed: it resets DeviceSettings to 1368×768, DRSEnabled=true, DRSTargetFPS=30, RenderScaleFSR=0.667 on the menu→game transition).

A potential hotfix should be considered for the currently available EA build, as it may also help with the proper functionality of 1.0 when it comes out.

Link to the original git page where the issue was discovered:

github.com/ValveSoftware/SteamOS

[Feature Request] SteamOS Automatic hardware detection

opened 11:47AM - 08 Jul 26 UTC

kahnakha

Hello All, After using SteamOS for quite some time now on many different system…s, including SteamDeck, ROG Ally, and an all AMD HTPC setup similar to the Steam Machine in terms of hardware specs, it came to me that for some reason SteamOS treats all of these systems as Steam Deck(even including the Steam Machine), and that's an issue for some games, where users are oftenly locked behind some limitations, for example not the full advanced graphical settings are available, or not the full screen resolution options are available, because the OS "thinks" it's a Steam Deck, thus limiting some games features to ensure the smoothest gameplay experience on the platform. I'm pretty sure, you can already see where the issue is. The workaround: Game Launch Options: `SteamDeck=0 %command%` This is "telling" the game that your system is in fact not a Steam Deck so that you can benefit from all ingame available settings, and features, so you can also utilize the available hardware. All of this is especially true for the Steam Machine, as it's way more capable then the Steam Deck, and we can only expect that most people simply want to start the system, and play their favorite titles without even thinking about all that, thus we cannot expect those same people to also be aware of these launch options, plus, they also don't always work too. The solution: Fully automatic, and hardware-aware process, so `SteamDeck=0` is only applied on non-Deck systems, while real Steam Deck hardware keeps its default behavior. The clean way to do this is to conditionally set the environment variable at login, based on actual hardware detection. What we know is that a real Steam Deck exposes identifiable system info via: DMI/BIOS strings (`/sys/class/dmi/id/*`) Vendor/model fields like: `Valve Jupiter` (LCD Deck) or `Galileo` (OLED Deck) So we can check those and decide: Is it a Real Deck? Yes, then keep SteamDeck=1 Anything else, force SteamDeck=0 Example of a detection script: ``` #!/bin/bash # Detect if running on actual Steam Deck hardware if grep -qiE "valve|jupiter|galileo" /sys/class/dmi/id/{sys_vendor,board_vendor,product_name,board_name} 2>/dev/null; then export SteamDeck=1 else export SteamDeck=0 fi ``` Example script file name: `steamdeck-detect.sh` And then just hook it into the environment `nano ~/.profile ` `source ~/.config/profile.d/steamdeck-detect.sh` All of this can also be introduced as a new feature as a trigger on the Steam UI, or in Gamescope, so that people can decide if they want to use the Deck profile, or the Desktop profile for their games, without the need of manually typing any commands anywhere. Please let me know what you think, and if this is even a feasible request. Thank You in advance.

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System variable detection causing game confusion

Environment

Root cause

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