diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 956207fcf..c2c08c2e9 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -475,14 +475,14 @@ add_library(core STATIC
     hle/service/am/service/process_winding_controller.h
     hle/service/am/service/self_controller.cpp
     hle/service/am/service/self_controller.h
+    hle/service/am/service/storage_accessor.cpp
+    hle/service/am/service/storage_accessor.h
     hle/service/am/service/system_applet_proxy.cpp
     hle/service/am/service/system_applet_proxy.h
     hle/service/am/system_buffer_manager.cpp
     hle/service/am/system_buffer_manager.h
     hle/service/am/spsm.cpp
     hle/service/am/spsm.h
-    hle/service/am/storage_accessor.cpp
-    hle/service/am/storage_accessor.h
     hle/service/am/storage.cpp
     hle/service/am/storage.h
     hle/service/am/window_controller.cpp
diff --git a/src/core/hle/service/am/service/storage_accessor.cpp b/src/core/hle/service/am/service/storage_accessor.cpp
new file mode 100644
index 000000000..84577fee4
--- /dev/null
+++ b/src/core/hle/service/am/service/storage_accessor.cpp
@@ -0,0 +1,68 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/hle/kernel/k_transfer_memory.h"
+#include "core/hle/service/am/library_applet_storage.h"
+#include "core/hle/service/am/service/storage_accessor.h"
+#include "core/hle/service/cmif_serialization.h"
+
+namespace Service::AM {
+
+IStorageAccessor::IStorageAccessor(Core::System& system_,
+                                   std::shared_ptr<LibraryAppletStorage> impl)
+    : ServiceFramework{system_, "IStorageAccessor"}, m_impl{std::move(impl)} {
+    static const FunctionInfo functions[] = {
+        {0, D<&IStorageAccessor::GetSize>, "GetSize"},
+        {10, D<&IStorageAccessor::Write>, "Write"},
+        {11, D<&IStorageAccessor::Read>, "Read"},
+    };
+
+    RegisterHandlers(functions);
+}
+
+IStorageAccessor::~IStorageAccessor() = default;
+
+Result IStorageAccessor::GetSize(Out<s64> out_size) {
+    LOG_DEBUG(Service_AM, "called");
+    *out_size = m_impl->GetSize();
+    R_SUCCEED();
+}
+
+Result IStorageAccessor::Write(InBuffer<BufferAttr_HipcAutoSelect> buffer, s64 offset) {
+    LOG_DEBUG(Service_AM, "called, offset={} size={}", offset, buffer.size());
+    R_RETURN(m_impl->Write(offset, buffer.data(), buffer.size()));
+}
+
+Result IStorageAccessor::Read(OutBuffer<BufferAttr_HipcAutoSelect> out_buffer, s64 offset) {
+    LOG_DEBUG(Service_AM, "called, offset={} size={}", offset, out_buffer.size());
+    R_RETURN(m_impl->Read(offset, out_buffer.data(), out_buffer.size()));
+}
+
+ITransferStorageAccessor::ITransferStorageAccessor(Core::System& system_,
+                                                   std::shared_ptr<LibraryAppletStorage> impl)
+    : ServiceFramework{system_, "ITransferStorageAccessor"}, m_impl{std::move(impl)} {
+    static const FunctionInfo functions[] = {
+        {0, D<&ITransferStorageAccessor::GetSize>, "GetSize"},
+        {1, D<&ITransferStorageAccessor::GetHandle>, "GetHandle"},
+    };
+
+    RegisterHandlers(functions);
+}
+
+ITransferStorageAccessor::~ITransferStorageAccessor() = default;
+
+Result ITransferStorageAccessor::GetSize(Out<s64> out_size) {
+    LOG_DEBUG(Service_AM, "called");
+    *out_size = m_impl->GetSize();
+    R_SUCCEED();
+}
+
+Result ITransferStorageAccessor::GetHandle(Out<s64> out_size,
+                                           OutCopyHandle<Kernel::KTransferMemory> out_handle) {
+    LOG_INFO(Service_AM, "called");
+    *out_size = m_impl->GetSize();
+    *out_handle = m_impl->GetHandle();
+    R_SUCCEED();
+}
+
+} // namespace Service::AM
diff --git a/src/core/hle/service/am/storage_accessor.h b/src/core/hle/service/am/service/storage_accessor.h
similarity index 54%
rename from src/core/hle/service/am/storage_accessor.h
rename to src/core/hle/service/am/service/storage_accessor.h
index b9aa85a66..1a01730e0 100644
--- a/src/core/hle/service/am/storage_accessor.h
+++ b/src/core/hle/service/am/service/storage_accessor.h
@@ -3,35 +3,36 @@
 
 #pragma once
 
-#include "core/hle/service/am/storage.h"
+#include "core/hle/service/am/library_applet_storage.h"
+#include "core/hle/service/cmif_types.h"
 #include "core/hle/service/service.h"
 
 namespace Service::AM {
 
 class IStorageAccessor final : public ServiceFramework<IStorageAccessor> {
 public:
-    explicit IStorageAccessor(Core::System& system_, std::shared_ptr<LibraryAppletStorage> impl_);
+    explicit IStorageAccessor(Core::System& system_, std::shared_ptr<LibraryAppletStorage> impl);
     ~IStorageAccessor() override;
 
 private:
-    void GetSize(HLERequestContext& ctx);
-    void Write(HLERequestContext& ctx);
-    void Read(HLERequestContext& ctx);
+    Result GetSize(Out<s64> out_size);
+    Result Write(InBuffer<BufferAttr_HipcAutoSelect> buffer, s64 offset);
+    Result Read(OutBuffer<BufferAttr_HipcAutoSelect> out_buffer, s64 offset);
 
-    const std::shared_ptr<LibraryAppletStorage> impl;
+    const std::shared_ptr<LibraryAppletStorage> m_impl;
 };
 
 class ITransferStorageAccessor final : public ServiceFramework<ITransferStorageAccessor> {
 public:
     explicit ITransferStorageAccessor(Core::System& system_,
-                                      std::shared_ptr<LibraryAppletStorage> impl_);
+                                      std::shared_ptr<LibraryAppletStorage> impl);
     ~ITransferStorageAccessor() override;
 
 private:
-    void GetSize(HLERequestContext& ctx);
-    void GetHandle(HLERequestContext& ctx);
+    Result GetSize(Out<s64> out_size);
+    Result GetHandle(Out<s64> out_size, OutCopyHandle<Kernel::KTransferMemory> out_handle);
 
-    const std::shared_ptr<LibraryAppletStorage> impl;
+    const std::shared_ptr<LibraryAppletStorage> m_impl;
 };
 
 } // namespace Service::AM
diff --git a/src/core/hle/service/am/storage.cpp b/src/core/hle/service/am/storage.cpp
index 4e82afd1c..12d95eebd 100644
--- a/src/core/hle/service/am/storage.cpp
+++ b/src/core/hle/service/am/storage.cpp
@@ -3,8 +3,8 @@
 
 #include "core/hle/service/am/am_results.h"
 #include "core/hle/service/am/library_applet_storage.h"
+#include "core/hle/service/am/service/storage_accessor.h"
 #include "core/hle/service/am/storage.h"
-#include "core/hle/service/am/storage_accessor.h"
 #include "core/hle/service/ipc_helpers.h"
 
 namespace Service::AM {
diff --git a/src/core/hle/service/am/storage_accessor.cpp b/src/core/hle/service/am/storage_accessor.cpp
deleted file mode 100644
index a1184b065..000000000
--- a/src/core/hle/service/am/storage_accessor.cpp
+++ /dev/null
@@ -1,90 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include "core/hle/kernel/k_transfer_memory.h"
-#include "core/hle/service/am/am_results.h"
-#include "core/hle/service/am/library_applet_storage.h"
-#include "core/hle/service/am/storage_accessor.h"
-#include "core/hle/service/ipc_helpers.h"
-
-namespace Service::AM {
-
-IStorageAccessor::IStorageAccessor(Core::System& system_,
-                                   std::shared_ptr<LibraryAppletStorage> impl_)
-    : ServiceFramework{system_, "IStorageAccessor"}, impl{std::move(impl_)} {
-    static const FunctionInfo functions[] = {
-        {0, &IStorageAccessor::GetSize, "GetSize"},
-        {10, &IStorageAccessor::Write, "Write"},
-        {11, &IStorageAccessor::Read, "Read"},
-    };
-
-    RegisterHandlers(functions);
-}
-
-IStorageAccessor::~IStorageAccessor() = default;
-
-void IStorageAccessor::GetSize(HLERequestContext& ctx) {
-    LOG_DEBUG(Service_AM, "called");
-
-    IPC::ResponseBuilder rb{ctx, 4};
-
-    rb.Push(ResultSuccess);
-    rb.Push(impl->GetSize());
-}
-
-void IStorageAccessor::Write(HLERequestContext& ctx) {
-    IPC::RequestParser rp{ctx};
-
-    const s64 offset{rp.Pop<s64>()};
-    const auto data{ctx.ReadBuffer()};
-    LOG_DEBUG(Service_AM, "called, offset={}, size={}", offset, data.size());
-
-    const auto res{impl->Write(offset, data.data(), data.size())};
-
-    IPC::ResponseBuilder rb{ctx, 2};
-    rb.Push(res);
-}
-
-void IStorageAccessor::Read(HLERequestContext& ctx) {
-    IPC::RequestParser rp{ctx};
-
-    const s64 offset{rp.Pop<s64>()};
-    std::vector<u8> data(ctx.GetWriteBufferSize());
-
-    LOG_DEBUG(Service_AM, "called, offset={}, size={}", offset, data.size());
-
-    const auto res{impl->Read(offset, data.data(), data.size())};
-
-    ctx.WriteBuffer(data);
-
-    IPC::ResponseBuilder rb{ctx, 2};
-    rb.Push(res);
-}
-
-ITransferStorageAccessor::ITransferStorageAccessor(Core::System& system_,
-                                                   std::shared_ptr<LibraryAppletStorage> impl_)
-    : ServiceFramework{system_, "ITransferStorageAccessor"}, impl{std::move(impl_)} {
-    static const FunctionInfo functions[] = {
-        {0, &ITransferStorageAccessor::GetSize, "GetSize"},
-        {1, &ITransferStorageAccessor::GetHandle, "GetHandle"},
-    };
-
-    RegisterHandlers(functions);
-}
-
-ITransferStorageAccessor::~ITransferStorageAccessor() = default;
-
-void ITransferStorageAccessor::GetSize(HLERequestContext& ctx) {
-    IPC::ResponseBuilder rb{ctx, 4};
-    rb.Push(ResultSuccess);
-    rb.Push(impl->GetSize());
-}
-
-void ITransferStorageAccessor::GetHandle(HLERequestContext& ctx) {
-    IPC::ResponseBuilder rb{ctx, 4, 1};
-    rb.Push(ResultSuccess);
-    rb.Push(impl->GetSize());
-    rb.PushCopyObjects(impl->GetHandle());
-}
-
-} // namespace Service::AM