MHW16x10Fix

An aspect ratio fix and black bar remover for Monster Hunter: World / Iceborne. It removes the forced 16:9 letterbox (top and bottom black bars) and enables native 16:10 rendering, including the Steam Deck's 1280x800 display. Both DX11 and DX12 are supported.

Useful search terms: MHW aspect ratio fix, remove black bars, letterbox remover, 16:10 fix, 1280x800 fix, Steam Deck mod, widescreen fix, DX11, and DX12.

How it works

The game normally requests render aspect mode 1, which constrains content to 16:9. This proxy waits for the first graphics Present and calls the game's own aspect-mode setter with mode 0 (no aspect crop). The engine then rebuilds the content area at the actual output size.

The fix does not stretch a 720-high image, patch the projection matrix, resize textures manually, or globally rewrite viewports/scissors.

Verified configuration

• Monster Hunter: World / Iceborne 15.23.00
• Steam executable SHA-256: C2EBBBD2C49F216D484E31A5219BED419EB1E5E7D206D02CBA040A3AB79D90EA
• DX11
• DX12
• 1280x800
• Windows and Steam Deck
• Steam Deck play session exceeding one hour without a crash
• SharpPluginLoader 0.0.9 on Windows and Steam Deck (DX12)

Other 16:10 and ultrawide resolutions may work through the same native mode, but have not received the same validation.

DX12 uses the same native engine setter and has been visually and internally validated on Windows and Steam Deck at 1280x800. SharpPluginLoader compatibility was also validated on both platforms. See the SharpPluginLoader compatibility guide for the required platform packages, Proton dependencies, and launch options.

Build

Requirements: Visual Studio 2022 with the Desktop development with C++ workload, and CMake 3.21 or newer.

cmake --preset vs2022-x64
cmake --build --preset release

The output directory contains dinput8.dll and mhw_16x10.ini.

Install

Copy both files beside MonsterHunterWorld.exe.

On SteamOS, use:

WINEDLLOVERRIDES="dinput8.dll=n,b" %command%

When SharpPluginLoader is also installed on Steam Deck, use its Linux package and the separately documented launch option instead. See SharpPluginLoader compatibility.

The game directory can contain only one file named dinput8.dll. To use another proxy mod at the same time:

1. Keep this project's DLL named dinput8.dll.
2. Rename the other mod's proxy DLL to dinput8_chain.dll.
3. Put both DLLs beside MonsterHunterWorld.exe.
4. Set ChainLoad=dinput8_chain.dll in mhw_16x10.ini.

Stracker's Loader must not receive forwarded DirectInput8Create calls after its proxy DLL is renamed, because its own forwarding path resolves back to the top-level dinput8.dll. For Stracker's Loader, also set:

ForwardDirectInput8Create=false

The configured path may also be absolute. Relative paths are resolved from the game directory.

Configuration

[Fix]
Enabled=true
AutoDetectAspect=true
Width=1280
Height=800
RemoveLetterbox=true

[Loader]
ChainLoad=
ForwardDirectInput8Create=true

[Debug]
EnableLog=true

With auto-detection enabled, the configured width and height are fallbacks. Logs are written to MHW16x10Fix.log.

When chain loading is configured, the downstream DLL is loaded before the first DirectInput call is completed. With ForwardDirectInput8Create=true, a downstream DirectInput8Create export receives the call. With the option set to false, the downstream DLL still receives its normal DllMain initialization while DirectInput calls continue directly to the Windows system DLL. The latter setting avoids recursive forwarding with Stracker's Loader. The default remains true for compatibility with other proxy DLLs. The log records which case occurred. Self-loading is rejected.

Compatibility guides

• SharpPluginLoader on Windows and Steam Deck

Limitations

• A small number of UI dialogs may retain 16:9-oriented positioning.
• Only the listed executable build is supported; the setter bytes are checked at runtime and an unknown build fails closed.
• Chain loading solves the common single-proxy filename conflict. It cannot guarantee compatibility between mods that hook or patch the same game or graphics functions, and a downstream proxy with its own hard-coded filename assumptions may still require that mod's documented loader arrangement.

Source and license

Source code: https://github.com/MinuteReversal/MHW16x10Fix

MHW16x10Fix is original work developed through runtime analysis and controlled testing. REFramework was consulted only as a high-level architectural reference for graphics API hooking; no REFramework source is included.

Licensed under the MIT License. You may use, modify, and redistribute the project, including commercially, provided the copyright and license notice are retained.