diff --git a/Source/Editor/Cooker/Steps/CookAssetsStep.cpp b/Source/Editor/Cooker/Steps/CookAssetsStep.cpp
index b9085da0d..0ba6ce861 100644
--- a/Source/Editor/Cooker/Steps/CookAssetsStep.cpp
+++ b/Source/Editor/Cooker/Steps/CookAssetsStep.cpp
@@ -368,11 +368,21 @@ bool CookAssetsStep::Process(CookingData& data, CacheData& cache, Asset* asset)
         // Virtual assets are not included into the build
         return false;
     }
+    const bool wasLoaded = asset->IsLoaded();
     if (asset->WaitForLoaded())
     {
         LOG(Error, "Failed to load asset \'{0}\'", asset->ToString());
         return true;
     }
+    if (!wasLoaded)
+    {
+        // HACK: give some time to resave any old assets in Asset::onLoad after it's loaded
+        // This assumes that if Load Thread enters Asset::Save then it will get asset lock and hold it until asset is saved
+        // So we can take the same lock to wait for save end but first we need to wait for it to get that lock
+        // (in future try to handle it in a better way)
+        Platform::Sleep(5);
+    }
+    ScopeLock lock(asset->Locker);
 
     // Switch based on an asset type
     const auto asBinaryAsset = dynamic_cast<BinaryAsset*>(asset);
diff --git a/Source/Engine/Content/BinaryAsset.cpp b/Source/Engine/Content/BinaryAsset.cpp
index deb39856e..a78618678 100644
--- a/Source/Engine/Content/BinaryAsset.cpp
+++ b/Source/Engine/Content/BinaryAsset.cpp
@@ -372,6 +372,7 @@ bool BinaryAsset::SaveToAsset(const StringView& path, AssetInitData& data, bool
         const auto locks = storage->_chunksLock;
         storage->_chunksLock = 0;
         result = storage->Save(data, silentMode);
+        ASSERT(storage->_chunksLock == 0);
         storage->_chunksLock = locks;
     }
     else
diff --git a/Source/Engine/Content/Storage/AssetHeader.h b/Source/Engine/Content/Storage/AssetHeader.h
index ad5c8efb9..f8cfeac75 100644
--- a/Source/Engine/Content/Storage/AssetHeader.h
+++ b/Source/Engine/Content/Storage/AssetHeader.h
@@ -20,7 +20,7 @@ typedef uint16 AssetChunksFlag;
 #define ALL_ASSET_CHUNKS MAX_uint16
 
 /// <summary>
-/// Flax Asset header
+/// Flax asset file header.
 /// </summary>
 struct FLAXENGINE_API AssetHeader
 {
@@ -51,34 +51,6 @@ public:
     }
 
 public:
-    /// <summary>
-    /// Gets the chunks.
-    /// </summary>
-    /// <param name="output">The output data.</param>
-    template<typename AllocationType = HeapAllocation>
-    void GetChunks(Array<FlaxChunk*, AllocationType>& output) const
-    {
-        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
-        {
-            if (Chunks[i] != nullptr)
-                output.Add(Chunks[i]);
-        }
-    }
-
-    /// <summary>
-    /// Gets the chunks that are loaded.
-    /// </summary>
-    /// <param name="output">The output data.</param>
-    template<typename AllocationType = HeapAllocation>
-    void GetLoadedChunks(Array<FlaxChunk*, AllocationType>& output) const
-    {
-        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
-        {
-            if (Chunks[i] != nullptr && Chunks[i]->IsLoaded())
-                output.Add(Chunks[i]);
-        }
-    }
-
     /// <summary>
     /// Gets the amount of created asset chunks.
     /// </summary>
@@ -95,14 +67,13 @@ public:
     void UnlinkChunks();
 
     /// <summary>
-    /// Gets string with a human-readable info about that header
+    /// Gets string with a human-readable info about that header.
     /// </summary>
-    /// <returns>Header info string</returns>
     String ToString() const;
 };
 
 /// <summary>
-/// Flax Asset header data
+/// Flax asset header with data.
 /// </summary>
 struct FLAXENGINE_API AssetInitData
 {
@@ -137,12 +108,5 @@ public:
     /// <summary>
     /// Gets the hash code.
     /// </summary>
-    uint32 GetHashCode() const
-    {
-        // Note: do not use Metadata/Dependencies because it may not be loaded (it's optional)
-        uint32 hashCode = GetHash(Header.ID);
-        hashCode = (hashCode * 397) ^ SerializedVersion;
-        hashCode = (hashCode * 397) ^ CustomData.Length();
-        return hashCode;
-    }
+    uint32 GetHashCode() const;
 };
diff --git a/Source/Engine/Content/Storage/FlaxFile.h b/Source/Engine/Content/Storage/FlaxFile.h
index 9a1da5244..b2fbac034 100644
--- a/Source/Engine/Content/Storage/FlaxFile.h
+++ b/Source/Engine/Content/Storage/FlaxFile.h
@@ -27,7 +27,10 @@ public:
     bool HasAsset(const Guid& id) const override;
     bool HasAsset(const AssetInfo& info) const override;
     int32 GetEntriesCount() const override;
-    void GetEntry(int32 index, Entry& output) const override;
+    void GetEntry(int32 index, Entry& value) const override;
+#if USE_EDITOR
+    void SetEntry(int32 index, const Entry& value) override;
+#endif
     void GetEntries(Array<Entry>& output) const override;
     void Dispose() override;
 
diff --git a/Source/Engine/Content/Storage/FlaxPackage.h b/Source/Engine/Content/Storage/FlaxPackage.h
index 11637c1b1..3afc0cdb8 100644
--- a/Source/Engine/Content/Storage/FlaxPackage.h
+++ b/Source/Engine/Content/Storage/FlaxPackage.h
@@ -28,7 +28,10 @@ public:
     bool HasAsset(const Guid& id) const override;
     bool HasAsset(const AssetInfo& info) const override;
     int32 GetEntriesCount() const override;
-    void GetEntry(int32 index, Entry& output) const override;
+    void GetEntry(int32 index, Entry& value) const override;
+#if USE_EDITOR
+    void SetEntry(int32 index, const Entry& value) override;
+#endif
     void GetEntries(Array<Entry>& output) const override;
     void Dispose() override;
 
diff --git a/Source/Engine/Content/Storage/FlaxStorage.cpp b/Source/Engine/Content/Storage/FlaxStorage.cpp
index 007238889..88c9a0d34 100644
--- a/Source/Engine/Content/Storage/FlaxStorage.cpp
+++ b/Source/Engine/Content/Storage/FlaxStorage.cpp
@@ -49,6 +49,15 @@ String AssetHeader::ToString() const
     return String::Format(TEXT("ID: {0}, TypeName: {1}, Chunks Count: {2}"), ID, TypeName, GetChunksCount());
 }
 
+uint32 AssetInitData::GetHashCode() const
+{
+    // Do not use Metadata/Dependencies because it may not be loaded (it's optional)
+    uint32 hashCode = GetHash(Header.ID);
+    hashCode = (hashCode * 397) ^ SerializedVersion;
+    hashCode = (hashCode * 397) ^ CustomData.Length();
+    return hashCode;
+}
+
 void FlaxChunk::RegisterUsage()
 {
     LastAccessTime = Platform::GetTimeSeconds();
@@ -605,6 +614,65 @@ bool FlaxStorage::Reload()
     return failed;
 }
 
+bool FlaxStorage::ReloadSilent()
+{
+    ScopeLock lock(_loadLocker);
+    if (!IsLoaded())
+        return false;
+
+    // Open file
+    auto stream = OpenFile();
+    if (stream == nullptr)
+        return true;
+
+    // Magic Code
+    uint32 magicCode;
+    stream->ReadUint32(&magicCode);
+    if (magicCode != MagicCode)
+    {
+        LOG(Warning, "Invalid asset magic code in {0}", ToString());
+        return true;
+    }
+
+    // Version
+    uint32 version;
+    stream->ReadUint32(&version);
+    if (version == 9)
+    {
+        _version = version;
+
+        // Custom storage data
+        CustomData customData;
+        stream->Read(customData);
+
+        // Entries
+        int32 assetsCount;
+        stream->ReadInt32(&assetsCount);
+        if (assetsCount != GetEntriesCount())
+        {
+            LOG(Warning, "Incorrect amount of assets ({} instead of {}) saved in {}", assetsCount, GetEntriesCount(), ToString());
+            return true;
+        }
+        for (int32 i = 0; i < assetsCount; i++)
+        {
+            SerializedEntryV9 se;
+            stream->ReadBytes(&se, sizeof(se));
+            Entry e(se.ID, se.TypeName.Data, se.Address);
+            SetEntry(i, e);
+        }
+
+        // TODO: load chunks metadata? compare against loaded chunks?
+    }
+    else
+    {
+        // Fallback to full reload
+        LOG(Warning, "Fallback to full reload of {0}", ToString());
+        Reload();
+    }
+
+    return false;
+}
+
 #endif
 
 bool FlaxStorage::LoadAssetHeader(const Guid& id, AssetInitData& data)
@@ -809,7 +877,7 @@ FlaxChunk* FlaxStorage::AllocateChunk()
 
 #if USE_EDITOR
 
-bool FlaxStorage::Create(const StringView& path, const AssetInitData* data, int32 dataCount, bool silentMode, const CustomData* customData)
+bool FlaxStorage::Create(const StringView& path, Span<AssetInitData> assets, bool silentMode, const CustomData* customData)
 {
     PROFILE_CPU();
     ZoneText(*path, path.Length());
@@ -824,24 +892,32 @@ bool FlaxStorage::Create(const StringView& path, const AssetInitData* data, int3
         return true;
 
     // Create package
-    bool result = Create(stream, data, dataCount, customData);
+    bool result = Create(stream, assets, customData);
 
     // Close file
     Delete(stream);
 
-    // Reload storage container (only if not in silent mode)
-    if (storage && !silentMode)
+    // Reload storage container
+    if (storage && storage->IsLoaded())
     {
-        storage->Reload();
+        if (silentMode)
+        {
+            // Silent data-only reload (loaded chunks location in file has been updated)
+            storage->ReloadSilent();
+        }
+        else
+        {
+            // Full reload
+            storage->Reload();
+        }
     }
 
     return result;
 }
 
-bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 dataCount, const CustomData* customData)
+bool FlaxStorage::Create(WriteStream* stream, Span<AssetInitData> assets, const CustomData* customData)
 {
-    // Validate inputs
-    if (data == nullptr || dataCount <= 0)
+    if (assets.Get() == nullptr || assets.Length() <= 0)
     {
         LOG(Warning, "Cannot create new package. No assets to write.");
         return true;
@@ -849,27 +925,31 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
 
     // Prepare data
     Array<SerializedEntryV9, InlinedAllocation<1>> entries;
-    entries.Resize(dataCount);
+    entries.Resize(assets.Length());
     Array<FlaxChunk*> chunks;
-
-    // Get all chunks
-    for (int32 i = 0; i < dataCount; i++)
-        data[i].Header.GetLoadedChunks(chunks);
-    int32 chunksCount = chunks.Count();
+    for (const AssetInitData& asset : assets)
+    {
+        for (FlaxChunk* chunk : asset.Header.Chunks)
+        {
+            if (chunk && chunk->IsLoaded())
+                chunks.Add(chunk);
+        }
+    }
+    const int32 chunksCount = chunks.Count();
 
     // TODO: sort chunks by size? smaller ones first?
     // Calculate start address of the first asset header location
     // 0 -> Header -> Entries Count -> Entries -> Chunks Count -> Chunk Locations
     int32 currentAddress = sizeof(Header)
             + sizeof(int32)
-            + sizeof(SerializedEntryV9) * dataCount
+            + sizeof(SerializedEntryV9) * assets.Length()
             + sizeof(int32)
             + (sizeof(FlaxChunk::Location) + sizeof(int32)) * chunksCount;
 
     // Initialize entries offsets in the file
-    for (int32 i = 0; i < dataCount; i++)
+    for (int32 i = 0; i < assets.Length(); i++)
     {
-        auto& asset = data[i];
+        const AssetInitData& asset = assets[i];
         entries[i] = SerializedEntryV9(asset.Header.ID, asset.Header.TypeName, currentAddress);
 
         // Move forward by asset header data size
@@ -934,8 +1014,8 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
     stream->Write(mainHeader);
 
     // Write asset entries
-    stream->WriteInt32(dataCount);
-    stream->WriteBytes(entries.Get(), sizeof(SerializedEntryV9) * dataCount);
+    stream->WriteInt32(assets.Length());
+    stream->WriteBytes(entries.Get(), sizeof(SerializedEntryV9) * assets.Length());
 
     // Write chunk locations and meta
     stream->WriteInt32(chunksCount);
@@ -948,20 +1028,18 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
     }
 
 #if ASSETS_LOADING_EXTRA_VERIFICATION
-
     // Check calculated position of first asset header
-    if (dataCount > 0 && stream->GetPosition() != entries[0].Address)
+    if (assets.Length() > 0 && stream->GetPosition() != entries[0].Address)
     {
         LOG(Warning, "Error while asset header location computation.");
         return true;
     }
-
 #endif
 
     // Write asset headers
-    for (int32 i = 0; i < dataCount; i++)
+    for (int32 i = 0; i < assets.Length(); i++)
     {
-        auto& header = data[i];
+        const AssetInitData& header = assets[i];
 
         // ID
         stream->Write(header.Header.ID);
@@ -974,9 +1052,10 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
         stream->WriteUint32(header.SerializedVersion);
 
         // Chunks mapping
-        for (FlaxChunk* chunk : header.Header.Chunks)
+        for (const FlaxChunk* chunk : header.Header.Chunks)
         {
             const int32 index = chunks.Find(chunk);
+            ASSERT_LOW_LAYER(index >= -1 && index <= ALL_ASSET_CHUNKS);
             stream->WriteInt32(index);
         }
 
@@ -998,14 +1077,12 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
     }
 
 #if ASSETS_LOADING_EXTRA_VERIFICATION
-
     // Check calculated position of first asset chunk
     if (chunksCount > 0 && stream->GetPosition() != chunks[0]->LocationInFile.Address)
     {
         LOG(Warning, "Error while asset data chunk location computation.");
         return true;
     }
-
 #endif
 
     // Write chunks data
@@ -1033,7 +1110,7 @@ bool FlaxStorage::Create(WriteStream* stream, const AssetInitData* data, int32 d
     return false;
 }
 
-bool FlaxStorage::Save(AssetInitData& data, bool silentMode)
+bool FlaxStorage::Save(const AssetInitData& data, bool silentMode)
 {
     // Check if can modify the storage
     if (!AllowDataModifications())
@@ -1475,12 +1552,21 @@ int32 FlaxFile::GetEntriesCount() const
     return _asset.ID.IsValid() ? 1 : 0;
 }
 
-void FlaxFile::GetEntry(int32 index, Entry& output) const
+void FlaxFile::GetEntry(int32 index, Entry& value) const
 {
     ASSERT(index == 0);
-    output = _asset;
+    value = _asset;
 }
 
+#if USE_EDITOR
+
+void FlaxFile::SetEntry(int32 index, const Entry& value)
+{
+    ASSERT(index == 0);
+    _asset = value;
+}
+#endif
+
 void FlaxFile::GetEntries(Array<Entry>& output) const
 {
     if (_asset.ID.IsValid())
@@ -1544,19 +1630,36 @@ int32 FlaxPackage::GetEntriesCount() const
     return _entries.Count();
 }
 
-void FlaxPackage::GetEntry(int32 index, Entry& output) const
+void FlaxPackage::GetEntry(int32 index, Entry& value) const
 {
     ASSERT(index >= 0 && index < _entries.Count());
     for (auto i = _entries.Begin(); i.IsNotEnd(); ++i)
     {
         if (index-- <= 0)
         {
-            output = i->Value;
+            value = i->Value;
             return;
         }
     }
 }
 
+#if USE_EDITOR
+
+void FlaxPackage::SetEntry(int32 index, const Entry& value)
+{
+    ASSERT(index >= 0 && index < _entries.Count());
+    for (auto i = _entries.Begin(); i.IsNotEnd(); ++i)
+    {
+        if (index-- <= 0)
+        {
+            i->Value = value;
+            return;
+        }
+    }
+}
+
+#endif
+
 void FlaxPackage::GetEntries(Array<Entry>& output) const
 {
     _entries.GetValues(output);
diff --git a/Source/Engine/Content/Storage/FlaxStorage.h b/Source/Engine/Content/Storage/FlaxStorage.h
index 09e8c0bdd..0d5965311 100644
--- a/Source/Engine/Content/Storage/FlaxStorage.h
+++ b/Source/Engine/Content/Storage/FlaxStorage.h
@@ -313,8 +313,17 @@ public:
     /// Gets the asset entry at given index.
     /// </summary>
     /// <param name="index">The asset index.</param>
-    /// <param name="output">The output.</param>
-    virtual void GetEntry(int32 index, Entry& output) const = 0;
+    /// <param name="value">The result.</param>
+    virtual void GetEntry(int32 index, Entry& value) const = 0;
+
+#if USE_EDITOR
+    /// <summary>
+    /// Sets the asset entry at given index.
+    /// </summary>
+    /// <param name="index">The asset index.</param>
+    /// <param name="value">The input value.</param>
+    virtual void SetEntry(int32 index, const Entry& value) = 0;
+#endif
 
     /// <summary>
     /// Gets all the entries in the storage.
@@ -424,62 +433,58 @@ public:
 
 public:
 #if USE_EDITOR
-
     /// <summary>
     /// Saves the specified asset data to the storage container.
     /// </summary>
     /// <param name="data">The data to save.</param>
     /// <param name="silentMode">In silent mode don't reload opened storage container that is using target file.</param>
     /// <returns>True if cannot save, otherwise false</returns>
-    bool Save(AssetInitData& data, bool silentMode = false);
+    bool Save(const AssetInitData& data, bool silentMode = false);
 
     /// <summary>
     /// Creates new FlaxFile using specified asset data.
     /// </summary>
     /// <param name="path">The file path.</param>
-    /// <param name="data">The data to write.</param>
+    /// <param name="asset">The asset data to write.</param>
     /// <param name="silentMode">In silent mode don't reload opened storage container that is using target file.</param>
     /// <param name="customData">Custom options.</param>
     /// <returns>True if cannot create package, otherwise false</returns>
-    FORCE_INLINE static bool Create(const StringView& path, const AssetInitData& data, bool silentMode = false, const CustomData* customData = nullptr)
+    FORCE_INLINE static bool Create(const StringView& path, const AssetInitData& asset, bool silentMode = false, const CustomData* customData = nullptr)
     {
-        return Create(path, &data, 1, silentMode, customData);
+        return Create(path, ToSpan(&asset, 1), silentMode, customData);
     }
 
     /// <summary>
     /// Creates new FlaxFile using specified assets data.
     /// </summary>
     /// <param name="path">The file path.</param>
-    /// <param name="data">The data to write.</param>
+    /// <param name="assets">The assets data to write.</param>
     /// <param name="silentMode">In silent mode don't reload opened storage container that is using target file.</param>
     /// <param name="customData">Custom options.</param>
     /// <returns>True if cannot create package, otherwise false</returns>
-    FORCE_INLINE static bool Create(const StringView& path, const Array<AssetInitData>& data, bool silentMode = false, const CustomData* customData = nullptr)
+    FORCE_INLINE static bool Create(const StringView& path, const Array<AssetInitData>& assets, bool silentMode = false, const CustomData* customData = nullptr)
     {
-        return Create(path, data.Get(), data.Count(), silentMode, customData);
+        return Create(path, ToSpan(assets), silentMode, customData);
     }
 
     /// <summary>
     /// Creates new FlaxFile using specified assets data.
     /// </summary>
     /// <param name="path">The file path.</param>
-    /// <param name="data">The data to write.</param>
-    /// <param name="dataCount">The data size.</param>
+    /// <param name="assets">The assets data to write.</param>
     /// <param name="silentMode">In silent mode don't reload opened storage container that is using target file.</param>
     /// <param name="customData">Custom options.</param>
     /// <returns>True if cannot create package, otherwise false</returns>
-    static bool Create(const StringView& path, const AssetInitData* data, int32 dataCount, bool silentMode = false, const CustomData* customData = nullptr);
+    static bool Create(const StringView& path, Span<AssetInitData> assets, bool silentMode = false, const CustomData* customData = nullptr);
 
     /// <summary>
     /// Creates new FlaxFile using specified assets data.
     /// </summary>
     /// <param name="stream">The output stream.</param>
-    /// <param name="data">The data to write.</param>
-    /// <param name="dataCount">The data size.</param>
+    /// <param name="assets">The assets data to write.</param>
     /// <param name="customData">Custom options.</param>
     /// <returns>True if cannot create package, otherwise false</returns>
-    static bool Create(WriteStream* stream, const AssetInitData* data, int32 dataCount, const CustomData* customData = nullptr);
-
+    static bool Create(WriteStream* stream, Span<AssetInitData> assets, const CustomData* customData = nullptr);
 #endif
 
 protected:
@@ -488,4 +493,5 @@ protected:
     virtual void AddEntry(Entry& e) = 0;
     FileReadStream* OpenFile();
     virtual bool GetEntry(const Guid& id, Entry& e) = 0;
+    bool ReloadSilent();
 };