diff --git a/src/serialization/impl/file.cpp b/src/serialization/impl/file.cpp
index 969d9dd14f497132b7ddd03f04425bec43d51ae8..0d2e43414fd6a721c94a6ba50359d590b922a860 100644
--- a/src/serialization/impl/file.cpp
+++ b/src/serialization/impl/file.cpp
@@ -33,7 +33,7 @@ public:
 
     void rewind() override { std::rewind(m_fptr); }
 
-    void skip(size_t bytes) override {
+    void skip(int64_t bytes) override {
         auto err = fseek(m_fptr, bytes, SEEK_CUR);
         mgb_assert(!err);
     }
@@ -104,7 +104,7 @@ public:
 
     void rewind() override { m_offset = 0; }
 
-    void skip(size_t bytes) override {
+    void skip(int64_t bytes) override {
         m_offset += bytes;
         mgb_assert(m_offset <= m_size);
     }
@@ -146,7 +146,7 @@ public:
         m_offset = 0;
     }
 
-    void skip(size_t bytes) override {
+    void skip(int64_t bytes) override {
         m_offset += bytes;
         mgb_assert(m_offset <= m_size);
     }
diff --git a/src/serialization/impl/serializer_oss.cpp b/src/serialization/impl/serializer_oss.cpp
index 6d3183f57ad0d25dd9ea6f9727c25dee22f36425..fb03d04d59d2c72f9f71d6fe6c92722736d04c96 100644
--- a/src/serialization/impl/serializer_oss.cpp
+++ b/src/serialization/impl/serializer_oss.cpp
@@ -838,25 +838,22 @@ GraphLoader::LoadResult GraphLoaderOSS::load(const LoadConfig& config, bool rewi
     // Read fbs::Graph
     uint32_t size;
     m_file->read(&size, sizeof(size));
-    m_graph_buf = m_file->read_shared(size);
+    m_file->skip(-sizeof(size));
+    m_graph_buf = m_file->read_shared(size + sizeof(size));
 
     // Rewind back to tensor data
     m_file->rewind();
     m_file->skip(tensor_begin);
 
-    mgb_throw_if(
-            !fbs::GraphBufferHasIdentifier(m_graph_buf.data()), SerializationError,
-            "invalid fbs model");
-
     {
         flatbuffers::Verifier verifier(
                 static_cast<const uint8_t*>(m_graph_buf.data()), m_graph_buf.size());
         mgb_throw_if(
-                !fbs::VerifyGraphBuffer(verifier), SerializationError,
+                !fbs::VerifySizePrefixedGraphBuffer(verifier), SerializationError,
                 "model verification failed (invalid or corrupted model?)");
     }
 
-    m_graph = fbs::GetGraph(m_graph_buf.data());
+    m_graph = fbs::GetSizePrefixedGraph(m_graph_buf.data());
     m_mgb_version = m_graph->mgb_version();
     if (m_graph->mgb_version() > MGB_VERSION) {
         mgb_log_warn(
diff --git a/src/serialization/impl/serializer_oss_v2.cpp b/src/serialization/impl/serializer_oss_v2.cpp
index f0c5a4a3c721a9899e11668d0cfb68a93f98923a..c1e94e14aa12e5d3415e8d6860a7027930c26496 100644
--- a/src/serialization/impl/serializer_oss_v2.cpp
+++ b/src/serialization/impl/serializer_oss_v2.cpp
@@ -801,21 +801,18 @@ GraphLoader::LoadResult GraphLoaderOSSV2::load(const LoadConfig& config, bool re
     // Read fbs::Graph
     uint32_t size;
     m_file->read(&size, sizeof(size));
-    m_model_buf = m_file->read_shared(size);
-
-    mgb_throw_if(
-            !fbs::v2::ModelBufferHasIdentifier(m_model_buf.data()), SerializationError,
-            "invalid fbs model");
+    m_file->skip(-sizeof(size));
+    m_model_buf = m_file->read_shared(size + sizeof(size));
 
     {
         flatbuffers::Verifier verifier(
                 static_cast<const uint8_t*>(m_model_buf.data()), m_model_buf.size());
         mgb_throw_if(
-                !fbs::v2::VerifyModelBuffer(verifier), SerializationError,
+                !fbs::v2::VerifySizePrefixedModelBuffer(verifier), SerializationError,
                 "model verification failed (invalid or corrupted model?)");
     }
 
-    m_model = fbs::v2::GetModel(m_model_buf.data());
+    m_model = fbs::v2::GetSizePrefixedModel(m_model_buf.data());
     m_mgb_version = m_model->mge_version();
     m_model_version = m_model->model_version();
     if (m_model->mge_version() > MGB_VERSION) {
diff --git a/src/serialization/include/megbrain/serialization/file.h b/src/serialization/include/megbrain/serialization/file.h
index d1d9d66e232f172b3b90812bc215765f93c4ea76..8fc1b2a009ebd9a2f77da51fd343c7c3d65d1a10 100644
--- a/src/serialization/include/megbrain/serialization/file.h
+++ b/src/serialization/include/megbrain/serialization/file.h
@@ -33,7 +33,7 @@ public:
     virtual void rewind() = 0;
 
     //! skip given number of bytes
-    virtual void skip(size_t bytes) = 0;
+    virtual void skip(int64_t bytes) = 0;
 
     //! read data into buffer
     virtual void read(void* dst, size_t size) = 0;
diff --git a/toolchains/ios.toolchain.cmake b/toolchains/ios.toolchain.cmake
index c57174ff0c4dedf07a04eb727fa0c3efa1832a47..ab6b9ff9307fa349db1b7327e74e832febbed0f5 100644
--- a/toolchains/ios.toolchain.cmake
+++ b/toolchains/ios.toolchain.cmake
@@ -217,10 +217,10 @@ if(NOT DEFINED IOS_DEPLOYMENT_TARGET)
         "2.0"
         CACHE STRING "Minimum iOS version to build for.")
   else()
-    # Unless specified, SDK version 10.0 is used by default as minimum target version
+    # Unless specified, SDK version 11.0 is used by default as minimum target version
     # (iOS, tvOS).
     set(IOS_DEPLOYMENT_TARGET
-        "10.0"
+        "11.0"
         CACHE STRING "Minimum iOS version to build for.")
   endif()
   message(