diff --git a/libraries/libstratosphere/include/stratosphere/fs.hpp b/libraries/libstratosphere/include/stratosphere/fs.hpp
index 7ecf5abae..98800f5a4 100644
--- a/libraries/libstratosphere/include/stratosphere/fs.hpp
+++ b/libraries/libstratosphere/include/stratosphere/fs.hpp
@@ -32,7 +32,7 @@
 #include "fs/fs_path_tool.hpp"
 #include "fs/fs_path_utils.hpp"
 #include "fs/fs_romfs_filesystem.hpp"
-#include "fs/fs_data.hpp"
+#include "fs/impl/fs_data.hpp"
 #include "fs/fs_system_data.hpp"
 #include "fs/fs_content_storage.hpp"
 #include "fs/fs_game_card.hpp"
diff --git a/libraries/libstratosphere/include/stratosphere/fs/fs_system_data.hpp b/libraries/libstratosphere/include/stratosphere/fs/fs_system_data.hpp
index 43cba17ee..e89ef8824 100644
--- a/libraries/libstratosphere/include/stratosphere/fs/fs_system_data.hpp
+++ b/libraries/libstratosphere/include/stratosphere/fs/fs_system_data.hpp
@@ -18,9 +18,9 @@
 
 namespace ams::fs {
 
-    Result QueryMountSystemDataCacheSize(size_t *out, ncm::ProgramId data_id);
+    Result QueryMountSystemDataCacheSize(size_t *out, ncm::DataId data_id);
 
-    Result MountSystemData(const char *name, ncm::ProgramId data_id);
-    Result MountSystemData(const char *name, ncm::ProgramId data_id, void *cache_buffer, size_t cache_size);
+    Result MountSystemData(const char *name, ncm::DataId data_id);
+    Result MountSystemData(const char *name, ncm::DataId data_id, void *cache_buffer, size_t cache_size);
 
 }
diff --git a/libraries/libstratosphere/include/stratosphere/fs/fs_data.hpp b/libraries/libstratosphere/include/stratosphere/fs/impl/fs_data.hpp
similarity index 56%
rename from libraries/libstratosphere/include/stratosphere/fs/fs_data.hpp
rename to libraries/libstratosphere/include/stratosphere/fs/impl/fs_data.hpp
index 0fb4d4068..4db782114 100644
--- a/libraries/libstratosphere/include/stratosphere/fs/fs_data.hpp
+++ b/libraries/libstratosphere/include/stratosphere/fs/impl/fs_data.hpp
@@ -14,14 +14,14 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #pragma once
-#include "fs_common.hpp"
+#include <stratosphere/fs/fs_common.hpp>
 
 namespace ams::fs::impl {
 
-    Result QueryMountDataCacheSize(size_t *out, ncm::ProgramId data_id, ncm::StorageId storage_id);
+    Result QueryMountDataCacheSize(size_t *out, ncm::DataId data_id, ncm::StorageId storage_id);
 
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id);
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size);
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_data_cache, bool use_path_cache);
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id);
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size);
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_data_cache, bool use_path_cache);
 
 }
diff --git a/libraries/libstratosphere/source/fs/fs_data.cpp b/libraries/libstratosphere/source/fs/fs_data.cpp
index b1d78d58f..4d7135b34 100644
--- a/libraries/libstratosphere/source/fs/fs_data.cpp
+++ b/libraries/libstratosphere/source/fs/fs_data.cpp
@@ -20,10 +20,10 @@ namespace ams::fs::impl {
 
     namespace {
 
-        Result OpenDataStorageByDataId(std::unique_ptr<ams::fs::IStorage> *out, ncm::ProgramId data_id, ncm::StorageId storage_id) {
+        Result OpenDataStorageByDataId(std::unique_ptr<ams::fs::IStorage> *out, ncm::DataId data_id, ncm::StorageId storage_id) {
             /* Open storage using libnx bindings. */
             ::FsStorage s;
-            R_TRY_CATCH(fsOpenDataStorageByDataId(std::addressof(s), static_cast<u64>(data_id), static_cast<::NcmStorageId>(storage_id))) {
+            R_TRY_CATCH(fsOpenDataStorageByDataId(std::addressof(s), data_id.value, static_cast<::NcmStorageId>(storage_id))) {
                 R_CONVERT(ncm::ResultContentMetaNotFound, fs::ResultTargetNotFound());
             } R_END_TRY_CATCH;
 
@@ -34,7 +34,7 @@ namespace ams::fs::impl {
             return ResultSuccess();
         }
 
-        Result MountDataImpl(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_cache, bool use_data_cache, bool use_path_cache) {
+        Result MountDataImpl(const char *name, ncm::DataId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_cache, bool use_data_cache, bool use_path_cache) {
             std::unique_ptr<fs::IStorage> storage;
             R_TRY(OpenDataStorageByDataId(std::addressof(storage), data_id, storage_id));
 
@@ -47,7 +47,7 @@ namespace ams::fs::impl {
 
     }
 
-    Result QueryMountDataCacheSize(size_t *out, ncm::ProgramId data_id, ncm::StorageId storage_id) {
+    Result QueryMountDataCacheSize(size_t *out, ncm::DataId data_id, ncm::StorageId storage_id) {
         R_UNLESS(out != nullptr, fs::ResultNullptrArgument());
 
         std::unique_ptr<fs::IStorage> storage;
@@ -61,14 +61,14 @@ namespace ams::fs::impl {
         return ResultSuccess();
     }
 
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id) {
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id) {
         /* Validate the mount name. */
         R_TRY(impl::CheckMountName(name));
 
         return MountDataImpl(name, data_id, storage_id, nullptr, 0, false, false, false);
     }
 
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size) {
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size) {
         /* Validate the mount name. */
         R_TRY(impl::CheckMountName(name));
 
@@ -77,7 +77,7 @@ namespace ams::fs::impl {
         return MountDataImpl(name, data_id, storage_id, cache_buffer, cache_size, true, false, false);
     }
 
-    Result MountData(const char *name, ncm::ProgramId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_data_cache, bool use_path_cache) {
+    Result MountData(const char *name, ncm::DataId data_id, ncm::StorageId storage_id, void *cache_buffer, size_t cache_size, bool use_data_cache, bool use_path_cache) {
         /* Validate the mount name. */
         R_TRY(impl::CheckMountName(name));
 
diff --git a/libraries/libstratosphere/source/fs/fs_system_data.cpp b/libraries/libstratosphere/source/fs/fs_system_data.cpp
index 6f7db7b71..3231e330c 100644
--- a/libraries/libstratosphere/source/fs/fs_system_data.cpp
+++ b/libraries/libstratosphere/source/fs/fs_system_data.cpp
@@ -18,15 +18,15 @@
 
 namespace ams::fs {
 
-    Result QueryMountSystemDataCacheSize(size_t *out, ncm::ProgramId data_id) {
+    Result QueryMountSystemDataCacheSize(size_t *out, ncm::DataId data_id) {
         return impl::QueryMountDataCacheSize(out, data_id, ncm::StorageId::BuiltInSystem);
     }
 
-    Result MountSystemData(const char *name, ncm::ProgramId data_id) {
+    Result MountSystemData(const char *name, ncm::DataId data_id) {
         return impl::MountData(name, data_id, ncm::StorageId::BuiltInSystem);
     }
 
-    Result MountSystemData(const char *name, ncm::ProgramId data_id, void *cache_buffer, size_t cache_size) {
+    Result MountSystemData(const char *name, ncm::DataId data_id, void *cache_buffer, size_t cache_size) {
         return impl::MountData(name, data_id, ncm::StorageId::BuiltInSystem, cache_buffer, cache_size);
     }
 
diff --git a/stratosphere/ams_mitm/source/set_mitm/setsys_mitm_service.cpp b/stratosphere/ams_mitm/source/set_mitm/setsys_mitm_service.cpp
index 9bbf89df1..dc2cf1b35 100644
--- a/stratosphere/ams_mitm/source/set_mitm/setsys_mitm_service.cpp
+++ b/stratosphere/ams_mitm/source/set_mitm/setsys_mitm_service.cpp
@@ -35,17 +35,17 @@ namespace ams::mitm::settings {
             }
 
             /* Mount firmware version data archive. */
-            R_ABORT_UNLESS(romfsMountFromDataArchive(ncm::SystemDataId::SystemVersion.value, NcmStorageId_BuiltInSystem, "sysver"));
             {
-                ON_SCOPE_EXIT { romfsUnmount("sysver"); };
+                R_ABORT_UNLESS(ams::fs::MountSystemData("sysver", ncm::SystemDataId::SystemVersion));
+                ON_SCOPE_EXIT { ams::fs::Unmount("sysver"); };
 
                 /* Firmware version file must exist. */
-                FILE *fp = fopen("sysver:/file", "rb");
-                AMS_ABORT_UNLESS(fp != nullptr);
-                ON_SCOPE_EXIT { fclose(fp); };
+                ams::fs::FileHandle file;
+                R_ABORT_UNLESS(ams::fs::OpenFile(std::addressof(file), "sysver:/file", fs::OpenMode_Read));
+                ON_SCOPE_EXIT { ams::fs::CloseFile(file); };
 
                 /* Must be possible to read firmware version from file. */
-                AMS_ABORT_UNLESS(fread(&g_firmware_version, sizeof(g_firmware_version), 1, fp) == 1);
+                R_ABORT_UNLESS(ams::fs::ReadFile(file, 0, std::addressof(g_firmware_version), sizeof(g_firmware_version)));
 
                 g_ams_firmware_version = g_firmware_version;
             }