# YimMenuV2 Anticheat Bypass Techniques: How the Menu Evades GTA Online Detection

> Discover YimMenuV2 anticheat bypass techniques including hash manipulation, native function interception, FSL module detection, and BattlEye patching to stay hidden in GTA Online.

- Repository: [YimMenu/YimMenuV2](https://github.com/YimMenu/YimMenuV2)
- Tags: deep-dive
- Published: 2026-07-16

---

**YimMenuV2 employs a multi-layered anticheat bypass system that manipulates internal integrity hashes, intercepts native script functions, detects external FSL modules, and patches BattlEye status routines to remain undetected in GTA Online.**

YimMenuV2 is an open-source mod menu for GTA Online that implements sophisticated countermeasures against Rockstar's anticheat systems. The `AnticheatBypass` module located in [`src/game/backend/AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/src/game/backend/AnticheatBypass.cpp) serves as the primary defense mechanism, enabling the menu to operate in "Vanilla", "FSL", or "Legit BattlEye" modes depending on the host environment.

## Overriding the Anticheat Integrity Hash

The first layer of protection involves replacing the in-memory `Obf32` structure that the anticheat uses to verify client integrity. In [`AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/AnticheatBypass.cpp) at lines 39-47, the menu initializes or overwrites the `AnticheatInitializedHash` pointer with a constant validation value.

```cpp
// Inside AnticheatBypass::RunOnStartupImpl()
if (!*Pointers.AnticheatInitializedHash) {
    *Pointers.AnticheatInitializedHash = new rage::Obf32;
    (*Pointers.AnticheatInitializedHash)->setData(0x124EA49D);
} else {
    // The hash was already allocated – just overwrite it
    (*Pointers.AnticheatInitializedHash)->setData(0x124EA49D);
}

```

By setting the hash to `0x124EA49D`, the menu convinces the anticheat that the game client has passed integrity verification, preventing detection of the menu's presence.

## Hooking NET_GAMESERVER_BEGIN_SERVICE

The second technique intercepts critical native calls used for server-side validation. Specifically, the `NET_GAMESERVER_BEGIN_SERVICE` native is hooked to block anticheat verification transactions.

```cpp
static void TransactionHook(rage::scrNativeCallContext* ctx)
{
    // The native receives a special transaction ID when the anticheat checks us.
    if (ctx->GetArg<int>(3) == -50712147) {
        // Force the call to return FALSE → verification fails.
        return ctx->SetReturnValue(FALSE);
    }
    // Otherwise forward to the original native.
    return NativeInvoker::GetNativeHandler(NativeIndex::NET_GAMESERVER_BEGIN_SERVICE)(ctx);
}

// Register the hook during script execution
NativeHooks::AddHook("shop_controller"_J,
                     NativeIndex::NET_GAMESERVER_BEGIN_SERVICE,
                     &TransactionHook);

```

When the transaction argument equals `-50712147` (the anticheat verification identifier), the hook forces a `FALSE` return value, effectively cancelling the server's validation request. This implementation resides in [`AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/AnticheatBypass.cpp) lines 26-33.

## FSL Lawnchair Module Detection

YimMenuV2 implements compatibility with the "Lawnchair" Freemode Super Loader (FSL) by detecting duplicate `WINMM.dll` modules in memory. The `CheckForFSL` utility function counts loaded instances of the DLL—more than one indicates FSL injection.

```cpp
bool CheckForFSL()
{
    int count = 0;
    for (auto& module : ModuleMgr.GetModules())
        if (module.first == "WINMM.dll"_J)
            ++count;
    return count > 1;          // Two copies => FSL is present
}

```

If FSL is detected, the menu locates the module exporting `LawnchairGetVersion`, `LawnchairIsProvidingLocalSaves`, and `LawnchairIsProvidingBattlEyeBypass`. When `LawnchairIsProvidingBattlEyeBypass` returns true, YimMenuV2 disables its own patches to avoid conflicts. This logic spans lines 55-89 in [`AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/AnticheatBypass.cpp).

## BattlEye Status Update Patching

When neither FSL-provided bypass nor a genuine BattlEye process is detected, the menu applies a byte-patch to prevent status updates from reaching Rockstar's servers. The `BattlEyeStatusUpdatePatch` pointer defined in [`src/game/pointers/Pointers.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/src/game/pointers/Pointers.cpp) is applied at lines 99-102 of [`AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/AnticheatBypass.cpp).

```cpp
if (!m_FSLProvidesBEBypass && !m_BattlEyeRunning) {
    // This patch stops the game from sending an "anticheat-alive" packet.
    Pointers.BattlEyeStatusUpdatePatch->Apply();
}

```

This patch halts the game's ability to transmit anticheat heartbeat signals, rendering BattlEye unaware of the client's actual state.

## Continuous Anticheat Flag Neutralization

The final defensive layer operates in a perpetual loop to maintain the bypass state. The menu continuously zeroes out three critical memory locations: `BERestartStatus`, `NeedsBERestart`, and `IsBEBanned`.

```cpp
while (true) {
    if (!m_FSLProvidesBEBypass && !m_BattlEyeRunning) {
        *Pointers.BERestartStatus = 0;
        *Pointers.NeedsBERestart = false;
        *Pointers.IsBEBanned      = false;
    }
    ScriptMgr::Yield(); // Yield to the script engine each tick
}

```

Located at lines 103-110 in [`AnticheatBypass.cpp`](https://github.com/YimMenu/YimMenuV2/blob/main/AnticheatBypass.cpp), this routine ensures that even if the game attempts to flag the player for anticheat violations, the flags are instantly reset before any action can be taken.

## Summary

- **Hash Manipulation**: Overwrites the `Obf32` anticheat validation structure with `0x124EA49D` to fake integrity checks.
- **Native Interception**: Hooks `NET_GAMESERVER_BEGIN_SERVICE` to block transaction ID `-50712147` and prevent server-side verification.
- **FSL Integration**: Detects duplicate `WINMM.dll` modules and queries Lawnchair exports to determine if external bypasses are active.
- **Memory Patching**: Applies `BattlEyeStatusUpdatePatch` to stop anticheat status transmissions when no external bypass is present.
- **Flag Maintenance**: Continuously clears `BERestartStatus`, `NeedsBERestart`, and `IsBEBanned` in a background loop to prevent ban flags from persisting.

## Frequently Asked Questions

### How does YimMenuV2 detect if FSL is already providing anticheat bypass?

The menu scans for multiple instances of `WINMM.dll` loaded in the process memory. If `CheckForFSL` finds more than one copy, it locates the module exporting `LawnchairGetVersion` and queries `LawnchairIsProvidingBattlEyeBypass`. When this export returns true, YimMenuV2 assumes FSL handles the bypass and disables its own patches to prevent conflicts.

### What is the significance of the transaction ID -50712147 in the native hook?

This specific integer value is the identifier Rockstar's anticheat uses when requesting client verification via the `NET_GAMESERVER_BEGIN_SERVICE` native. By intercepting calls with this argument and forcing a `FALSE` return value, the menu prevents the server from completing its anticheat handshake while allowing legitimate transactions to proceed normally.

### Why does the menu overwrite the anticheat hash with 0x124EA49D?

The `Obf32` structure at `AnticheatInitializedHash` stores the anticheat's internal integrity validation state. By overwriting this with the constant `0x124EA49D` during `RunOnStartupImpl`, the menu pre-emptively satisfies the anticheat's self-check routine, causing it to skip deeper integrity scans that would otherwise detect the injected menu code.

### What happens if BattlEye is legitimately running when YimMenuV2 starts?

If the menu detects a genuine BattlEye process at startup, it sets `m_BattlEyeRunning` to true and skips applying the `BattlEyeStatusUpdatePatch` and flag-clearing loops. The menu operates in "Legit BattlEye" mode, printing this status at initialization to indicate that native anticheat bypasses are inactive to avoid detection by the active BattlEye client.