Add Firmware 20.0.0-21.0.0 IPC support and stubs

This commit implements comprehensive firmware 20.0.0 through 21.0.0
support for Citron, including:

- Updated firmware version constants to 21.0.0 in api_version.h
- Updated HID service firmware version string to 21.0.0
- Added IPC command stubs for firmware 20.0.0+ in:
  * ISystemSettingsServer (commands 263, 264, 282, 283, 289, 300, 301, 306, 307)
  * IFirmwareDebugSettingsServer (command 24)
  * IApplicationFunctions (command 330)
  * IOlscServiceForSystemService (command 914)
  * IRemoteStorageController (commands 28, 901)
  * IService (migration) (commands 2250, 2260)
  * IAudioController (command 10200)

- Created new service interfaces with proper stubs:
  * IContinuousRecorder (grcsrv) - command 5 [20.2.0+] with 0x20-byte input
  * IDownloadContext (news) - command 4 [20.0.0+]
  * INotifyService (pdm:ntfy) - commands 100, 101 [20.0.0+] returning outinterfaces

- Added all new source files to CMakeLists.txt build system
- Fixed logging tag usage (Service_Migration instead of Service_MIG)
- Added required CMIF serialization headers for proper template instantiation

All stubs return success explicitly, eliminating the need for auto-stubbing.
All implementations follow Switchbrew documentation as closely as possible.

Based on Switchbrew documentation:
- https://switchbrew.org/wiki/21.0.0
- https://switchbrew.org/wiki/20.5.0
- https://switchbrew.org/wiki/20.4.0
- https://switchbrew.org/wiki/20.3.0
- https://switchbrew.org/wiki/20.2.0
- https://switchbrew.org/wiki/20.1.5
- https://switchbrew.org/wiki/20.1.1
- https://switchbrew.org/wiki/20.1.0
- https://switchbrew.org/wiki/20.0.1
- https://switchbrew.org/wiki/20.0.0

Signed-off-by: Zephyron <zephyron@citron-emu.org>

src/core/CMakeLists.txt

@@ -581,6 +581,8 @@ add_library(core STATIC
     hle/service/bcat/delivery_cache_storage_service.h
     hle/service/bcat/delivery_task_suspension_service.cpp
     hle/service/bcat/delivery_task_suspension_service.h
+    hle/service/bcat/news/download_context.cpp
+    hle/service/bcat/news/download_context.h
     hle/service/bcat/news/newly_arrived_event_holder.cpp
     hle/service/bcat/news/newly_arrived_event_holder.h
     hle/service/bcat/news/news_data_service.cpp
@@ -721,6 +723,8 @@ add_library(core STATIC
     hle/service/glue/time/time_zone_binary.h
     hle/service/glue/time/worker.cpp
     hle/service/glue/time/worker.h
+    hle/service/grc/continuous_recorder.cpp
+    hle/service/grc/continuous_recorder.h
     hle/service/grc/grc.cpp
     hle/service/grc/grc.h
     hle/service/hid/active_vibration_device_list.cpp
@@ -853,6 +857,8 @@ add_library(core STATIC
     hle/service/ns/language.h
     hle/service/ns/ns.cpp
     hle/service/ns/ns.h
+    hle/service/ns/notify_service.cpp
+    hle/service/ns/notify_service.h
     hle/service/ns/ns_results.h
     hle/service/ns/ns_types.h
     hle/service/ns/platform_service_manager.cpp

src/core/hle/api_version.h

@@ -12,8 +12,8 @@ namespace HLE::ApiVersion {
 
 // Horizon OS version constants.
 
-constexpr u8 HOS_VERSION_MAJOR = 20;
-constexpr u8 HOS_VERSION_MINOR = 4;
+constexpr u8 HOS_VERSION_MAJOR = 21;
+constexpr u8 HOS_VERSION_MINOR = 0;
 constexpr u8 HOS_VERSION_MICRO = 0;
 
 // NintendoSDK version constants.
@@ -22,9 +22,9 @@ constexpr u8 SDK_REVISION_MAJOR = 1;
 constexpr u8 SDK_REVISION_MINOR = 0;
 
 constexpr char PLATFORM_STRING[] = "NX";
-constexpr char VERSION_HASH[] = "cc744ded0c0eb7b0a71917a97ec00926427cd652";
-constexpr char DISPLAY_VERSION[] = "20.4.0";
-constexpr char DISPLAY_TITLE[] = "NintendoSDK Firmware for NX 20.4.0-1.0";
+constexpr char VERSION_HASH[] = "f6b2425b6888a66590db104fc734891696e0ecb3";
+constexpr char DISPLAY_VERSION[] = "21.0.0";
+constexpr char DISPLAY_TITLE[] = "NintendoSDK Firmware for NX 21.0.0-1.0";
 
 // Atmosphere version constants.
 

src/core/hle/service/am/service/application_functions.cpp

@@ -91,6 +91,7 @@ IApplicationFunctions::IApplicationFunctions(Core::System& system_, std::shared_
         {300, nullptr, "RequestToLaunchApplication"},
         {301, nullptr, "RequestToLaunchApplicationWithUserAndArguments"},
         {310, nullptr, "RequestToLaunchApplicationWithArgumentsAndUserSelectionAndError"},
+        {330, D<&IApplicationFunctions::Unknown330>, "Unknown330"}, // [20.2.0+]
         {350, nullptr, "DeclareApplicationAlive"},
         {400, nullptr, "CreateApplicationResourceUsageSystemReportForDebug"},
         {401, nullptr, "WriteApplicationResourceUsageSystemReportForDebug"},
@@ -526,4 +527,9 @@ Result IApplicationFunctions::GetLaunchRequiredVersionUpgrade(OutCopyHandle<Kern
     R_SUCCEED();
 }
 
+Result IApplicationFunctions::Unknown330() {
+    LOG_WARNING(Service_AM, "(STUBBED) called Unknown330 [20.2.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::AM

src/core/hle/service/am/service/application_functions.h

@@ -78,6 +78,7 @@ private:
     Result GetHealthWarningDisappearedSystemEvent(OutCopyHandle<Kernel::KReadableEvent> out_event);
     Result PrepareForJit();
     Result GetLaunchRequiredVersionUpgrade(OutCopyHandle<Kernel::KReadableEvent> out_event);
+    Result Unknown330(); // [20.2.0+]
 
     const std::shared_ptr<Applet> m_applet;
 };

src/core/hle/service/audio/audio_controller.cpp

@@ -73,7 +73,7 @@ IAudioController::IAudioController(Core::System& system_)
         {50003, D<&IAudioController::SetForceOverrideExternalDeviceNameForDebug>, "SetForceOverrideExternalDeviceNameForDebug"}, // [19.0.0+]
         {50004, D<&IAudioController::ClearForceOverrideExternalDeviceNameForDebug>, "ClearForceOverrideExternalDeviceNameForDebug"}, // [19.0.0+]
         {5000, nullptr, "Unknown5000"}, // [19.0.0+]
-        {10200, nullptr, "Unknown10200"}, // [20.0.0+]
+        {10200, D<&IAudioController::Unknown10200>, "Unknown10200"}, // [20.0.0+]
     };
     // clang-format on
 
@@ -402,4 +402,9 @@ Result IAudioController::ClearForceOverrideExternalDeviceNameForDebug() {
     R_SUCCEED();
 }
 
+Result IAudioController::Unknown10200() {
+    LOG_WARNING(Audio, "(STUBBED) called Unknown10200 [20.0.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::Audio

src/core/hle/service/audio/audio_controller.h

@@ -90,6 +90,7 @@ private:
     Result OverrideDefaultTargetForDebug(u32 target); // [19.0.0-19.0.1]
     Result SetForceOverrideExternalDeviceNameForDebug(InLargeData<std::array<u8, 0x80>, BufferAttr_HipcMapAlias> device_name); // [19.0.0+]
     Result ClearForceOverrideExternalDeviceNameForDebug(); // [19.0.0+]
+    Result Unknown10200(); // [20.0.0+]
 
     KernelHelpers::ServiceContext service_context;
 

src/core/hle/service/bcat/news/download_context.cpp

@@ -0,0 +1,32 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "common/logging/log.h"
+#include "core/hle/service/bcat/news/download_context.h"
+#include "core/hle/service/cmif_serialization.h"
+
+namespace Service::News {
+
+IDownloadContext::IDownloadContext(Core::System& system_)
+    : ServiceFramework{system_, "IDownloadContext"} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {0, nullptr, "Unknown0"},
+        {1, nullptr, "Unknown1"},
+        {2, nullptr, "Unknown2"},
+        {3, nullptr, "Unknown3"},
+        {4, D<&IDownloadContext::Unknown4>, "Unknown4"}, // [20.0.0+]
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+IDownloadContext::~IDownloadContext() = default;
+
+Result IDownloadContext::Unknown4() {
+    LOG_WARNING(Service_BCAT, "(STUBBED) called Unknown4 [20.0.0+]");
+    R_SUCCEED();
+}
+
+} // namespace Service::News

src/core/hle/service/bcat/news/download_context.h

@@ -0,0 +1,24 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include "core/hle/service/cmif_types.h"
+#include "core/hle/service/service.h"
+
+namespace Core {
+class System;
+}
+
+namespace Service::News {
+
+class IDownloadContext final : public ServiceFramework<IDownloadContext> {
+public:
+    explicit IDownloadContext(Core::System& system_);
+    ~IDownloadContext() override;
+
+private:
+    Result Unknown4(); // [20.0.0+]
+};
+
+} // namespace Service::News

src/core/hle/service/grc/continuous_recorder.cpp

@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "common/logging/log.h"
+#include "core/hle/service/cmif_serialization.h"
+#include "core/hle/service/grc/continuous_recorder.h"
+
+namespace Service::GRC {
+
+IContinuousRecorder::IContinuousRecorder(Core::System& system_)
+    : ServiceFramework{system_, "IContinuousRecorder"} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {0, nullptr, "Unknown0"},
+        {1, nullptr, "Unknown1"},
+        {2, nullptr, "Unknown2"},
+        {3, nullptr, "Unknown3"},
+        {4, nullptr, "Unknown4"},
+        {5, D<&IContinuousRecorder::Unknown5>, "Unknown5"}, // [20.2.0+] Takes 0x20-byte input
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+IContinuousRecorder::~IContinuousRecorder() = default;
+
+Result IContinuousRecorder::Unknown5(InBuffer<BufferAttr_HipcPointer> buffer) {
+    LOG_WARNING(Service_GRC, "(STUBBED) called Unknown5 [20.2.0+], buffer_size={}", buffer.size());
+    R_SUCCEED();
+}
+
+} // namespace Service::GRC

src/core/hle/service/grc/continuous_recorder.h

@@ -0,0 +1,24 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/hle/service/cmif_types.h"
+#include "core/hle/service/service.h"
+
+namespace Core {
+class System;
+}
+
+namespace Service::GRC {
+
+class IContinuousRecorder final : public ServiceFramework<IContinuousRecorder> {
+public:
+    explicit IContinuousRecorder(Core::System& system_);
+    ~IContinuousRecorder() override;
+
+private:
+    Result Unknown5(InBuffer<BufferAttr_HipcPointer> buffer); // [20.2.0+] Takes 0x20-byte input
+};
+
+} // namespace Service::GRC

src/core/hle/service/grc/grc.cpp

@@ -3,6 +3,8 @@
 
 #include <memory>
 
+#include "core/hle/service/cmif_serialization.h"
+#include "core/hle/service/grc/continuous_recorder.h"
 #include "core/hle/service/grc/grc.h"
 #include "core/hle/service/server_manager.h"
 #include "core/hle/service/service.h"
@@ -11,10 +13,10 @@ namespace Service::GRC {
 
 class GRC final : public ServiceFramework<GRC> {
 public:
-    explicit GRC(Core::System& system_) : ServiceFramework{system_, "grc:c"} {
+    explicit GRC(Core::System& system_) : ServiceFramework{system_, "grc:c"}, system{system_} {
         // clang-format off
         static const FunctionInfo functions[] = {
-            {1, nullptr, "OpenContinuousRecorder"},
+            {1, D<&GRC::OpenContinuousRecorder>, "OpenContinuousRecorder"},
             {2, nullptr, "OpenGameMovieTrimmer"},
             {3, nullptr, "OpenOffscreenRecorder"},
             {101, nullptr, "CreateMovieMaker"},
@@ -24,8 +26,18 @@ public:
 
         RegisterHandlers(functions);
     }
+
+private:
+    Result OpenContinuousRecorder(Out<SharedPointer<IContinuousRecorder>> out_interface);
+    Core::System& system;
 };
 
+Result GRC::OpenContinuousRecorder(Out<SharedPointer<IContinuousRecorder>> out_interface) {
+    LOG_WARNING(Service_GRC, "(STUBBED) called");
+    *out_interface = std::make_shared<IContinuousRecorder>(system);
+    R_SUCCEED();
+}
+
 void LoopProcess(Core::System& system) {
     auto server_manager = std::make_unique<ServerManager>(system);
 

src/core/hle/service/hid/hid_server.cpp

@@ -2165,7 +2165,7 @@ Result IHidServer::GetFirmwareVersionStringForUserSupportPage(OutBuffer<BufferAt
     LOG_WARNING(Service_HID, "(STUBBED) called, applet_resource_user_id={}", aruid.pid);
 
     // Return atmosphere's firmware version & NX version
-    constexpr std::string_view firmware_version = "20.1.5|AMS 1.9.1|E";
+    constexpr std::string_view firmware_version = "21.0.0|AMS 1.9.5|E";
     std::memcpy(out_firmware_version.data(), firmware_version.data(),
                 std::min(out_firmware_version.size(), firmware_version.size()));
 

src/core/hle/service/mig/mig.cpp

@@ -1,8 +1,11 @@
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <memory>
 
+#include "common/logging/log.h"
+#include "core/hle/service/cmif_serialization.h"
 #include "core/hle/service/mig/mig.h"
 #include "core/hle/service/server_manager.h"
 #include "core/hle/service/service.h"
@@ -24,14 +27,30 @@ public:
             {1100, nullptr, "Unknown1100"},
             {1101, nullptr, "Unknown1101"},
             {1200, nullptr, "Unknown1200"},
-            {1201, nullptr, "Unknown1201"}
+            {1201, nullptr, "Unknown1201"},
+            {2250, D<&MIG_USR::Unknown2250>, "Unknown2250"}, // [20.2.0+] interface version updated
+            {2260, D<&MIG_USR::Unknown2260>, "Unknown2260"}, // [20.2.0+] interface version updated
         };
         // clang-format on
 
         RegisterHandlers(functions);
     }
+
+private:
+    Result Unknown2250();
+    Result Unknown2260();
 };
 
+Result MIG_USR::Unknown2250() {
+    LOG_WARNING(Service_Migration, "(STUBBED) called Unknown2250 [20.2.0+]");
+    R_SUCCEED();
+}
+
+Result MIG_USR::Unknown2260() {
+    LOG_WARNING(Service_Migration, "(STUBBED) called Unknown2260 [20.2.0+]");
+    R_SUCCEED();
+}
+
 void LoopProcess(Core::System& system) {
     auto server_manager = std::make_unique<ServerManager>(system);
 

src/core/hle/service/ngc/ngc.cpp

@@ -142,6 +142,8 @@ private:
 void LoopProcess(Core::System& system) {
     auto server_manager = std::make_unique<ServerManager>(system);
 
+    // Note: In firmware 21.0.0+, the ngct sysmodule is stubbed and ngct:u service was moved into ngc.
+    // We keep both services registered for backward compatibility with older firmware versions.
     server_manager->RegisterNamedService("ngct:u", std::make_shared<NgctServiceImpl>(system));
     server_manager->RegisterNamedService("ngc:u", std::make_shared<NgcServiceImpl>(system));
     ServerManager::RunServer(std::move(server_manager));

src/core/hle/service/ns/notify_service.cpp

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "common/logging/log.h"
+#include "core/hle/service/cmif_serialization.h"
+#include "core/hle/service/ns/notify_service.h"
+#include "core/hle/service/ns/service_getter_interface.h"
+
+namespace Service::NS {
+
+INotifyService::INotifyService(Core::System& system_)
+    : ServiceFramework{system_, "pdm:ntfy"}, system{system_} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {0, nullptr, "Unknown0"},
+        {100, D<&INotifyService::Unknown100>, "Unknown100"}, // [20.0.0+]
+        {101, D<&INotifyService::Unknown101>, "Unknown101"}, // [20.0.0+]
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+INotifyService::~INotifyService() = default;
+
+Result INotifyService::Unknown100(Out<SharedPointer<IServiceGetterInterface>> out_interface) {
+    LOG_WARNING(Service_NS, "(STUBBED) called Unknown100 [20.0.0+]");
+    *out_interface = std::make_shared<IServiceGetterInterface>(system, "pdm:ntfy");
+    R_SUCCEED();
+}
+
+Result INotifyService::Unknown101(Out<SharedPointer<IServiceGetterInterface>> out_interface) {
+    LOG_WARNING(Service_NS, "(STUBBED) called Unknown101 [20.0.0+]");
+    *out_interface = std::make_shared<IServiceGetterInterface>(system, "pdm:ntfy");
+    R_SUCCEED();
+}
+
+} // namespace Service::NS

src/core/hle/service/ns/notify_service.h

@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/hle/service/cmif_types.h"
+#include "core/hle/service/service.h"
+
+namespace Service::NS {
+class IServiceGetterInterface;
+}
+
+namespace Core {
+class System;
+}
+
+namespace Service::NS {
+
+class INotifyService final : public ServiceFramework<INotifyService> {
+public:
+    explicit INotifyService(Core::System& system_);
+    ~INotifyService() override;
+
+private:
+    Result Unknown100(Out<SharedPointer<IServiceGetterInterface>> out_interface); // [20.0.0+]
+    Result Unknown101(Out<SharedPointer<IServiceGetterInterface>> out_interface); // [20.0.0+]
+    Core::System& system;
+};
+
+} // namespace Service::NS

src/core/hle/service/ns/ns.cpp

@@ -3,6 +3,7 @@
 
 #include "core/hle/service/ns/develop_interface.h"
 #include "core/hle/service/ns/ns.h"
+#include "core/hle/service/ns/notify_service.h"
 #include "core/hle/service/ns/platform_service_manager.h"
 #include "core/hle/service/ns/query_service.h"
 #include "core/hle/service/ns/service_getter_interface.h"
@@ -33,6 +34,7 @@ void LoopProcess(Core::System& system) {
     server_manager->RegisterNamedService("ns:vm",
                                          std::make_shared<IVulnerabilityManagerInterface>(system));
     server_manager->RegisterNamedService("pdm:qry", std::make_shared<IQueryService>(system));
+    server_manager->RegisterNamedService("pdm:ntfy", std::make_shared<INotifyService>(system));
 
     server_manager->RegisterNamedService("pl:s",
                                          std::make_shared<IPlatformServiceManager>(system, "pl:s"));

src/core/hle/service/olsc/olsc_service_for_system_service.cpp

@@ -48,6 +48,7 @@ IOlscServiceForSystemService::IOlscServiceForSystemService(Core::System& system_
         {911, nullptr, "CleanupSeriesInfoType1"},
         {912, nullptr, "RemoveSeriesInfoType1"},
         {913, nullptr, "GetSeriesInfoType1"},
+        {914, D<&IOlscServiceForSystemService::Unknown914>, "Unknown914"}, // [20.2.0+]
         {1000, nullptr, "UpdateIssueOld"},
         {1010, nullptr, "Unknown1010"},
         {1011, nullptr, "ListIssueInfoOld"},
@@ -114,4 +115,9 @@ Result IOlscServiceForSystemService::CloneService(
     R_SUCCEED();
 }
 
+Result IOlscServiceForSystemService::Unknown914() {
+    LOG_WARNING(Service_OLSC, "(STUBBED) called Unknown914 [20.2.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::OLSC

src/core/hle/service/olsc/olsc_service_for_system_service.h

@@ -22,6 +22,7 @@ private:
     Result OpenDaemonController(Out<SharedPointer<IDaemonController>> out_interface);
     Result GetDataTransferPolicyInfo(Out<u16> out_policy_info, u64 application_id);
     Result CloneService(Out<SharedPointer<IOlscServiceForSystemService>> out_interface);
+    Result Unknown914(); // [20.2.0+]
 };
 
 } // namespace Service::OLSC

src/core/hle/service/olsc/remote_storage_controller.cpp

@@ -33,7 +33,9 @@ IRemoteStorageController::IRemoteStorageController(Core::System& system_)
         {23, nullptr, "TouchSecondarySave"},
         {24, nullptr, "GetSecondarySaveDataInfo"},
         {25, nullptr, "RegisterDownloadSaveDataTransferTaskForAutonomyRegistration"},
+        {28, D<&IRemoteStorageController::Unknown28>, "Unknown28"}, // [20.2.0+]
         {900, nullptr, "Unknown900"},
+        {901, D<&IRemoteStorageController::Unknown901>, "Unknown901"}, // [20.2.0+]
     };
     // clang-format on
 
@@ -51,4 +53,14 @@ Result IRemoteStorageController::GetSecondarySave(Out<bool> out_has_secondary_sa
     R_SUCCEED();
 }
 
+Result IRemoteStorageController::Unknown28() {
+    LOG_WARNING(Service_OLSC, "(STUBBED) called Unknown28 [20.2.0+]");
+    R_SUCCEED();
+}
+
+Result IRemoteStorageController::Unknown901() {
+    LOG_WARNING(Service_OLSC, "(STUBBED) called Unknown901 [20.2.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::OLSC

src/core/hle/service/olsc/remote_storage_controller.h

@@ -14,6 +14,8 @@ public:
 private:
     Result GetSecondarySave(Out<bool> out_has_secondary_save, Out<std::array<u64, 3>> out_unknown,
                             u64 application_id);
+    Result Unknown28(); // [20.2.0+]
+    Result Unknown901(); // [20.2.0+]
 };
 
 } // namespace Service::OLSC

src/core/hle/service/set/firmware_debug_settings_server.cpp

@@ -1,6 +1,9 @@
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "common/logging/log.h"
+#include "core/hle/service/cmif_serialization.h"
 #include "core/hle/service/set/firmware_debug_settings_server.h"
 
 namespace Service::Set {
@@ -18,6 +21,7 @@ IFirmwareDebugSettingsServer::IFirmwareDebugSettingsServer(Core::System& system_
         {21, nullptr, "SetAllowedSslHosts"},
         {22, nullptr, "SetHostFsMountPoint"},
         {23, nullptr, "SetMemoryUsageRateFlag"},
+        {24, D<&IFirmwareDebugSettingsServer::Unknown24>, "Unknown24"}, // [20.0.0+]
     };
     // clang-format on
 
@@ -26,4 +30,9 @@ IFirmwareDebugSettingsServer::IFirmwareDebugSettingsServer(Core::System& system_
 
 IFirmwareDebugSettingsServer::~IFirmwareDebugSettingsServer() = default;
 
+Result IFirmwareDebugSettingsServer::Unknown24() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown24 [20.0.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::Set

src/core/hle/service/set/firmware_debug_settings_server.h

@@ -15,6 +15,9 @@ class IFirmwareDebugSettingsServer final : public ServiceFramework<IFirmwareDebu
 public:
     explicit IFirmwareDebugSettingsServer(Core::System& system_);
     ~IFirmwareDebugSettingsServer() override;
+
+private:
+    Result Unknown24(); // [20.0.0+]
 };
 
 } // namespace Service::Set

src/core/hle/service/set/system_settings_server.cpp

@@ -301,6 +301,15 @@ ISystemSettingsServer::ISystemSettingsServer(Core::System& system_)
         {208, nullptr, "SetHearingProtectionSafeguardFlag"},
         {209, nullptr, "GetHearingProtectionSafeguardRemainingTime"},
         {210, nullptr, "SetHearingProtectionSafeguardRemainingTime"},
+        {263, C<&ISystemSettingsServer::Unknown263>, "Unknown263"}, // [20.0.0+]
+        {264, C<&ISystemSettingsServer::Unknown264>, "Unknown264"}, // [20.0.0+]
+        {282, C<&ISystemSettingsServer::Unknown282>, "Unknown282"}, // [20.0.0+]
+        {283, C<&ISystemSettingsServer::Unknown283>, "Unknown283"}, // [20.0.0+]
+        {289, C<&ISystemSettingsServer::Unknown289>, "Unknown289"}, // [20.0.0+]
+        {300, C<&ISystemSettingsServer::Unknown300>, "Unknown300"}, // [20.0.0+]
+        {301, C<&ISystemSettingsServer::Unknown301>, "Unknown301"}, // [20.0.0+]
+        {306, C<&ISystemSettingsServer::Unknown306>, "Unknown306"}, // [20.0.0+]
+        {307, C<&ISystemSettingsServer::Unknown307>, "Unknown307"}, // [20.0.0+]
     };
     // clang-format on
 
@@ -1389,4 +1398,49 @@ Result ISystemSettingsServer::GetSettingsItemValueImpl(std::span<u8> out_value,
     R_SUCCEED();
 }
 
+Result ISystemSettingsServer::Unknown263() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown263 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown264() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown264 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown282() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown282 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown283() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown283 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown289() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown289 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown300() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown300 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown301() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown301 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown306() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown306 [20.0.0+]");
+    R_SUCCEED();
+}
+
+Result ISystemSettingsServer::Unknown307() {
+    LOG_WARNING(Service_SET, "(STUBBED) called Unknown307 [20.0.0+]");
+    R_SUCCEED();
+}
+
 } // namespace Service::Set

src/core/hle/service/set/system_settings_server.h

@@ -155,6 +155,15 @@ public:
     Result GetFieldTestingFlag(Out<bool> out_field_testing_flag);
     Result GetPanelCrcMode(Out<s32> out_panel_crc_mode);
     Result SetPanelCrcMode(s32 panel_crc_mode);
+    Result Unknown263(); // [20.0.0+]
+    Result Unknown264(); // [20.0.0+]
+    Result Unknown282(); // [20.0.0+]
+    Result Unknown283(); // [20.0.0+]
+    Result Unknown289(); // [20.0.0+]
+    Result Unknown300(); // [20.0.0+]
+    Result Unknown301(); // [20.0.0+]
+    Result Unknown306(); // [20.0.0+]
+    Result Unknown307(); // [20.0.0+]
 
 private:
     bool LoadSettingsFile(std::filesystem::path& path, auto&& default_func);