SCUM-AllowMods v0.1.0

⚠️ STATUS UPDATE — SCUM Hotfix (07.05.2026)

Gamepires has restored support for .pak loading on clients. For that standard modding workflow, this mod is no longer required.

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A drop-in install bundle that re-enables loading of unsigned PAK mods in SCUM after the developers blocked the -fileopenlog modding workflow in late April 2026.

This bundle contains:

• UE4SS Experimental v3.0.1-946 (commit 265115c0) — official upstream release
• The scum_allow_mods patch mod (28 KB)
• A pre-configured UE4SS-settings.ini with safe hook settings
• Built-in UE4SS mods (all disabled by default)
• Everything else needed — drop into Win64/, done

⚠️ USE AT YOUR OWN RISK — there is no guarantee against future bans. Read the entire README before installing.

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What this does

In late April 2026, the SCUM developers neutralized the -fileopenlog launch parameter that the modding community had relied on for asset modding. This blocked the engine's PAK signature validation from being bypassed via the CLI flag — meaning unsigned mod-PAKs could no longer be mounted by the game.

This bundle restores PAK modding by patching a UE 4.27.2 engine-internal validation function directly in the running game process:

1. On mod init, an AOB pattern scan locates the validation function in SCUM.exe.
2. The pattern matches twice (engine-typical paired prologue); the second match is the real target.
3. VirtualProtect opens the page for writing.
4. The first byte of the function is overwritten with 0xC3 (x86 RET).
5. The function returns immediately on every invocation — validation never runs — unsigned PAKs mount without rejection.

Verified working on client (SCUM.exe) — same approach also works on server (SCUMServer.exe) since both binaries use UE 4.27.2.

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Quick install

See INSTALL.txt at the top level of this bundle for a 6-step quick-start.

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Detailed install (Client)

Step 1 — Disable BattlEye

The Steam launch parameter -nobattleye alone is not enough. You also need to stop the BattlEye Windows service:

PowerShell as Administrator:

Stop-Service -Name BEService -Force
Set-Service -Name BEService -StartupType Disabled

If the kernel driver BEDaisy keeps loading after a reboot:

sc stop BEDaisy
sc config BEDaisy start= disabled

Step 2 — Extract this bundle

Extract everything in this bundle (next to INSTALL.txt) directly into:

<Steam>/steamapps/common/SCUM/SCUM/Binaries/Win64/

After extraction your Win64/ folder should contain:

Win64/
├── dwmapi.dll                      (from this bundle — UE4SS proxy DLL)
├── SCUM.exe                        (already there, game's own)
├── ue4ss/                          (from this bundle)
│   ├── UE4SS.dll
│   ├── UE4SS-settings.ini
│   ├── LICENSE                     (UE4SS license)
│   └── Mods/
│       ├── mods.txt
│       ├── scum_allow_mods/
│       │   ├── dlls/
│       │   │   └── main.dll
│       │   └── enabled.txt
│       └── (UE4SS built-in mods, all disabled by default)
└── (other game files left untouched)

Step 3 — Set Steam launch options

Steam → SCUM → Properties → Launch Options:

-nobattleye

Do NOT add -fileopenlog — this mod replaces it.

Step 4 — Launch SCUM directly

Steam's Play button still triggers the BattlEye launcher even with -nobattleye. Bypass it by launching SCUM.exe directly:

<Steam>/steamapps/common/SCUM/SCUM/Binaries/Win64/SCUM.exe

Easiest: create a desktop shortcut to this SCUM.exe, or use a Steam Custom Launcher tool.

Step 5 — Verify the mod loaded

Open <Win64>/ue4ss/UE4SS.log. Search for:

[ScumAllowMods]: Init.
[ScumAllowMods]: Delegate found and patched.

If you see Delegate not found. Unable to patch., the AOB pattern needs to be updated for the current SCUM build — see Troubleshooting.

Step 6 — Drop in your mods

Place your unsigned .pak files into:

<Steam>/steamapps/common/SCUM/SCUM/Content/Paks/~mods/

Re-launch SCUM. Check <SCUM>/Saved/Logs/SCUM.log for:

LogPakFile: Display: Mounting pak file ../../../SCUM/Content/Paks/~mods/YourMod_P.pak.

If the mount line appears, you're done. Connect to a server that has the same mod-PAKs (hash-match required) and play.

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Server-side install

If you run a SCUM dedicated server with custom unsigned mod-PAKs, you also need this mod server-side — otherwise your server's own engine refuses to mount them on boot.

Same procedure, but install to:

<ServerInstall>/SCUM/Binaries/Win64/ue4ss/Mods/scum_allow_mods/

The -fileopenlog flag also still works server-side at the moment, but this mod replaces it cleanly. Pick one — either flag, or this mod, not both.

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Important caveats

• Hash-match required for multiplayer: When you connect to a server, the server compares your mounted PAK list against its own. If they don't match, you get kicked. Use this on modded servers that have matching PAKs, or on your own server.
• No cheating: This mod re-enables asset/cosmetic modding only. It does not bypass server authority for gameplay (item spawning, position, stats — those are server-state). Don't expect this to enable cheats.
• Future SCUM updates may break it: If the developers refactor the validated function, the AOB pattern needs updating. PRs welcome.
• No ban guarantee: BattlEye is disabled while running this. Theoretically the developers could add server-side detection of modified clients in future updates.

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Troubleshooting

Delegate not found. Unable to patch. in UE4SS.log

The AOB pattern didn't match in the current SCUM.exe. A SCUM update changed the validation function's prologue. To fix:

1. Open SCUM.exe in IDA / Ghidra.
2. Find the function with the original prologue pattern (search for the disassembly shape: gs:[0x58] TLS access followed by indexed reads).
3. Update the AOB string in the source dllmain.cpp and rebuild.

See the GitHub repository for the source code and build instructions.

Game crashes with EXCEPTION_ACCESS_VIOLATION

Most often this is not caused by this mod, but by UE4SS itself. The bundle's UE4SS-settings.ini has all the recommended fixes pre-applied (all hooks off, bUseUObjectArrayCache = false, EngineVersionOverride set to 4.27). If you still get crashes:

1. Delete <Win64>/ue4ss/UE4SS_Cache_*.bin (force fresh AOB scan).
2. Verify all Hook* settings in <Win64>/ue4ss/UE4SS-settings.ini are 0 (you may have edited them).
3. If you installed other UE4SS mods, disable them one by one in mods.txt to find the culprit.

Mod loads but my PAK isn't mounted

Check SCUM.log (in <SCUM>/Saved/Logs/):

• Found Pak file ... attempting to mount. — engine sees your PAK.
• Mounting pak file ... — actual mount happened. ✅
• Anything mentioning signature, rejected, failed, or invalid — the patch isn't taking effect. Re-verify UE4SS.log shows Delegate found and patched.

If the PAK file isn't even seen by the engine, double-check the path:

<Steam>/steamapps/common/SCUM/SCUM/Content/Paks/~mods/YourMod_P.pak

The ~mods folder must exist; the underscore-suffix _P on the file name is required by UE4 for mod PAKs.

BattlEye keeps reactivating after reboot

If the BE service starts back up:

1. Confirm Set-Service -Name BEService -StartupType Disabled ran successfully.
2. Check services.msc — BE Service status should be "Disabled".
3. Some games re-install the BE service via Steam validation. If you ran "Verify Integrity of Game Files", BE may have been restored. Re-disable it.

Steam still launches BattlEye

The -nobattleye Steam launch option only suppresses Steam's wrapper — Steam itself may still trigger the BE launcher. Solution:

• Launch SCUM.exe directly (not through Steam's Play button).
• Use a Steam Custom Launcher tool that bypasses the wrapper.

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Credits

• Narknon & Truman — Original AllowModsMod for PAYDAY 3, whose architecture and patch approach inspired this bundle.
• UE4SS-RE Team — RE-UE4SS framework (Experimental v3.0.1-946 included).
• SKRYPT Community — SCUM-specific AOB pattern extraction + verification.

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Licenses

• scum_allow_mods: MIT — see LICENSE at top level.
• UE4SS framework: see ue4ss/LICENSE.