diff --git a/include/RED4ext/NativeTypes.hpp b/include/RED4ext/NativeTypes.hpp
index 325f31ba3..076a737ac 100644
--- a/include/RED4ext/NativeTypes.hpp
+++ b/include/RED4ext/NativeTypes.hpp
@@ -162,8 +162,8 @@ struct Variant
     Variant(CName aTypeName);
     Variant(CName aTypeName, const void* aData);
     template<typename T>
-    requires !std::derived_from<std::remove_pointer_t<std::decay_t<T>>, rtti::IType>
-             Variant(const T& acValue)
+    requires(!std::derived_from<std::remove_pointer_t<std::decay_t<T>>, rtti::IType>)
+    Variant(const T& acValue)
         : Variant(GetTypeName<T>(), std::addressof(acValue))
     {
     }
@@ -290,7 +290,7 @@ struct Variant
         {
             // TODO: support all game types and user types using RedLib solution:
             // https://github.com/psiberx/cp2077-red-lib/blob/master/include/Red/TypeInfo/Resolving.hpp
-            static_assert(false, "Type is currently unsupported.");
+            static_assert(!std::is_same_v<T, T>, "Type is currently unsupported.");
             return "";
         }
     }
diff --git a/include/RED4ext/TweakDB-inl.hpp b/include/RED4ext/TweakDB-inl.hpp
index 1518dceef..f25e3519c 100644
--- a/include/RED4ext/TweakDB-inl.hpp
+++ b/include/RED4ext/TweakDB-inl.hpp
@@ -324,17 +324,20 @@ RED4EXT_INLINE int32_t RED4ext::TweakDB::CreateFlatValue(const CStackType& aStac
 
     UpsizeFlatDataBuffer(MaxFlatDataBufferSize);
 
-    uintptr_t flatAlignment = (std::max)(aStackType.type->GetAlignment(), 8u);
-    uintptr_t flatValueSize = RED4ext::AlignUp(8ull /* vftable */ + aStackType.type->GetSize(), flatAlignment);
-    uintptr_t flatDataBufferEnd_Aligned = RED4ext::AlignUp(flatDataBufferEnd, flatAlignment);
+    const uintptr_t flatAlignment = (std::max)(aStackType.type->GetAlignment(), 8u);
+    const uintptr_t flatValueSize = RED4ext::AlignUp(8ull /* vftable */ + aStackType.type->GetSize(), flatAlignment);
+    const uintptr_t flatAddressAligned = RED4ext::AlignUp(flatDataBufferEnd, flatAlignment);
+    const uintptr_t newFlatDataBufferEnd = flatAddressAligned + flatValueSize;
 
-    if (AllocateFlatValue(reinterpret_cast<void*>(flatDataBufferEnd_Aligned), aStackType))
+    if (newFlatDataBufferEnd > (flatDataBuffer + flatDataBufferCapacity) ||
+        !AllocateFlatValue(reinterpret_cast<void*>(flatAddressAligned), aStackType))
     {
-        flatDataBufferEnd = flatDataBufferEnd_Aligned + flatValueSize;
-        return reinterpret_cast<FlatValue*>(flatDataBufferEnd_Aligned)->ToTDBOffset();
+        return -1;
     }
 
-    return -1;
+    flatDataBufferEnd = newFlatDataBufferEnd;
+
+    return reinterpret_cast<FlatValue*>(flatAddressAligned)->ToTDBOffset();
 }
 
 RED4EXT_INLINE bool RED4ext::TweakDB::AllocateFlatValue(void* aBuffer, const CStackType& aStackType)