NoArbitraryIncompatibilityFlag

A BepInEx patcher that removes incompatibility restrictions from RtD mods, allowing them to work alongside other popular Valheim mods.

What Does It Do?

This patcher removes [BepInIncompatibility] attributes from RtD mods, enabling you to use them together with mods that were previously blocked. The mods themselves work fine together - this simply removes the restrictions.

Affected RtD Mods:

• RtDOcean
• RtDVines
• RtDMonsters
• RtDSouls & RtDSouls_Addon
• RtDBiomes
• RtDMonstrum
• RtDDungeons
• RtDFairyTale
• RtDGardening
• RtDHorrors
• RtDItems
• RtDMagic

Previously Blocked Mods (Now Compatible):

• CookieMilk.MagicalMounts
• CookieMilk.MajesticChickens
• CookieMilk.BuildPieces
• CookieMilk.CarryMeMaster
• CookieMilk.DiscordControl
• CookieMilk.UltimateServerControl
• Therzie.MonstrumDeepNorth
• Therzie.WarfareFireAndIce
• Therzie.Monstrum
• Therzie.Armory
• Therzie.Wizardry
• Therzie.Warfare
• blacks7ar.MagicPlugin
• blacks7ar.MagicRevamp
• blacks7ar.SeedBed
• blacks7ar.OreMines
• blacks7ar.BowPlugin
• randyknapp.mods.epicloot

Installation

IMPORTANT: This is a PATCHER, not a regular plugin!

1. Download NoArbitraryIncompatibilityFlag.dll
2. Place it in BepInEx/patchers/ folder (NOT plugins!)
3. Launch the game
4. The patcher will automatically process RtD mods on startup

How It Works

The patcher runs during BepInEx's preloader phase and uses Harmony to patch .NET runtime methods:

1. Patches PluginInfo.Incompatibilities property getter to return empty array for RtD mods
2. Patches Dictionary.ContainsKey to hide our GUID when RtD mods check for us
3. Patches Assembly.GetName() to return a fake name when RtD mods scan loaded assemblies

All modifications are in-memory only and temporary. No files are ever modified on disk.

On launch, you'll see:

✓ Ready to bypass incompatibility checks for RtD mods
✓ Ready to hide from RtD mod detection
✓ Ready to hide assembly name from RtD mod detection
✓ Found RtD mod: RtDOcean
✓ Successfully bypassed incompatibility checks for 1 RtD mod(s)

Technical Details

How RtD Mods Detect This Patcher

RtD mods added three detection checks in their Awake() method:

1. IL Bytecode Integrity Check: Verifies their "Block" method hasn't been modified

   MethodInfo method = typeof(RtDMod).GetMethod("Block", ...);
   byte[] ilAsByteArray = method?.GetMethodBody()?.GetILAsByteArray();
   if (method == null || ilAsByteArray == null || ilAsByteArray.Length <= 2)
       Fail();
   

2. PluginInfo Dictionary Check: Looks for our GUID in BepInEx's plugin registry

   if (Chainloader.PluginInfos.ContainsKey("IAmOnTheInternetAndItIsScary.NoArbitraryIncompatibilityFlag"))
       Fail();
   

3. Assembly Name Scan: Searches all loaded assemblies for our name

   if (AppDomain.CurrentDomain.GetAssemblies().Any(a => a.GetName().Name.Contains("NoArbitraryIncompatibilityFlag")))
       Fail();
   

How This Patcher Works

The patcher uses Harmony to patch .NET runtime methods at the lowest level:

1. Incompatibility Bypass: Patch PluginInfo.Incompatibilities getter to return empty array for RtD mods

   • Intercepts the property access before RtD mods can read their incompatibility list
   • Only affects RtD mods (identified by "Soloredis." GUID prefix)

2. ContainsKey Stealth: Patch Dictionary<string, PluginInfo>.ContainsKey to return false when RtD mods check for our GUID

   • Uses stack trace analysis to identify when the caller is an RtD mod
   • Returns false only for our specific GUID and only when called from RtD code
   • All other dictionary operations work normally

3. Assembly Name Hiding: Patch Assembly.GetName() to return fake name when RtD mods scan assemblies

   • Returns "HiddenAssembly" instead of "NoArbitraryIncompatibilityFlag" when called from RtD mods
   • Uses caching to avoid performance issues from repeated assembly scanning
   • Other mods see the real assembly name

4. IL Check Passes Automatically: We don't modify RtD mod code at all, so their bytecode integrity check passes naturally

FAQ

Q: Is this safe?
A: Yes. The patcher only removes compatibility restrictions. The mods function normally, they just don't block other mods anymore.

Q: Will this break my game?
A: No. If you encounter any issues, they would be unrelated to this patcher. You can always remove the patcher to restore original behavior.

Q: Do I need to reinstall after RtD mod updates?
A: No. The patcher runs on every launch and automatically handles any RtD mod version.

Q: Can I upgrade from an older version of this patcher?
A: Yes. Just replace the old DLL with the new one in the patchers folder.

Q: Will this work with old versions of RtD mods?
A: Yes. The patcher works with all current RtD mod versions.

Q: What if I want to stop using this patcher?
A: Simply remove the DLL from the patchers folder. RtD mods will return to their original behavior.

Changelog

[1.1.2] - 2026-06-18

Changed

• Added support for two newly released RtD mods: RtDLegends and RtDMythics
• Expanded the target list to 15 RtD mods
• Both the GUID detection set and the patched DLL list now cover the new mods

[1.1.1] - 2026-04-06

Changed

• Updated FAQ to address false claims about patcher causing bugs or performance issues
• Clarified that blocked mods work perfectly with RtD mods
• Documentation improvements

[1.1.0] - 2026-04-06

Changed

• Package structure updated for automatic installation with mod managers
• DLL now included in patchers/ folder within the zip file
• Mod managers will now automatically place the patcher in the correct BepInEx/patchers/ directory
• No more manual file moving required when using mod managers

[1.0.9] - 2026-04-06

Changed

• Implemented dual-layer defense combining Cecil IL patching with Harmony runtime patches
• Cecil layer strips incompatibility attributes and neuters detection code before any plugin loads
• Harmony layer provides fallback protection for runtime detection attempts

Technical Details

This version uses a two-layer defense strategy:

Layer 1: Cecil IL Patching (runs before any code loads)

• Strips all [BepInIncompatibility] attributes from RtD mod types
• Neuters the Fail() method by replacing its body with just ret
• Removes throw statements from static constructor integrity checks
• NOPs all Fail() calls in Awake() method

Layer 2: Harmony Runtime Patches (fallback protection)

• Patches PluginInfo.Incompatibilities getter to return empty array
• Patches Dictionary.ContainsKey to hide our GUID
• Patches Assembly.GetName() to return fake name
• Patches AppDomain.GetAssemblies() to filter out our assembly with recursion guard

The Cecil layer handles the heavy lifting by modifying IL before execution. Even if RtD mods add new detection checks, they all ultimately call Fail(), which now does nothing. The Harmony patches remain as a safety net.

All modifications are in-memory only. BepInEx's patcher system loads DLLs into memory, passes them to our Patch() method as AssemblyDefinition objects, we modify the IL, and BepInEx loads the modified version into the CLR. Original DLLs on disk are never touched.

[1.0.8] - 2026-04-06

Changed

• Added runtime detection evasion for RtD mods
• Patcher now hides from all RtD detection mechanisms
• Assembly scanning is cached to prevent performance issues

Technical Details

RtD mods added detection checks in their Awake() method. The patcher uses Harmony to patch .NET runtime methods:

• Dictionary<string, PluginInfo>.ContainsKey returns false when RtD mods check for our GUID
• Assembly.GetName() returns a fake name when RtD mods scan loaded assemblies
• Stack trace analysis identifies RtD mods by their "Soloredis." GUID prefix
• All modifications remain in-memory only

[1.0.7] - 2026-04-04

Changed

• Switched to runtime Harmony patching
• All modifications now happen in-memory only
• Patches PluginInfo.Incompatibilities property getter at runtime

Technical Details

• Uses Harmony to intercept incompatibility checks
• Patches execute in BepInEx preloader Finish phase
• Returns empty incompatibility array for RtD mods

[1.0.6] - 2026-04-04

Changed

• Updated documentation to be strictly informational
• Removed informal language from documentation

[1.0.5] - 2026-04-04

Changed

• Updated patcher to handle integrity verification in RtD mods
• Modified approach to preserve method structures while bypassing compatibility checks

Technical Details

• RtD mods added integrity checks using IL bytecode inspection
• Patcher preserves original method structures to pass integrity verification
• Initialization flow is modified to skip compatibility checks

[1.0.4] - 2026-04-04

Changed

• Updated README with accurate log output examples
• Documentation improvements for clarity

[1.0.3] - 2026-04-04

Changed

• Rewrote detection code removal approach
• Now rebuilds initialization methods instead of patching IL instructions
• Reconstructs clean initialization flow without compatibility checks

Technical Details

• Rebuilds initialization methods to skip compatibility checks
• Clears problematic method bodies to prevent mod disabling
• More robust approach that works regardless of code structure

[1.0.2] - 2026-04-02

Changed

• Updated README to clarify that all RtD mods include compatibility restrictions
• Documentation accuracy improvements

[1.0.1] - 2026-04-02

Changed

• Updated README with additional documentation
• Added FAQ entries about compatibility handling

[1.0.0] - 2026-04-02

Changed

• Initial release
• Removes [BepInIncompatibility] attributes from all RtD mods
• Supports all 13 RtD mods (Ocean, Vines, Monsters, Souls, Biomes, Monstrum, Dungeons, FairyTale, Gardening, Horrors, Items, Magic, Souls_Addon)
• Removes blocks for 19 popular mods
• Automatic patching on game launch

Technical Details

• Patches DLL files using Mono.Cecil
• Works in BepInEx preloader phase
• Only patches when needed