diff --git a/libraries/libstratosphere/include/stratosphere/pm/impl/pm_boot_mode_interface.hpp b/libraries/libstratosphere/include/stratosphere/pm/impl/pm_boot_mode_interface.hpp
index a34f2272d..66faf57e2 100644
--- a/libraries/libstratosphere/include/stratosphere/pm/impl/pm_boot_mode_interface.hpp
+++ b/libraries/libstratosphere/include/stratosphere/pm/impl/pm_boot_mode_interface.hpp
@@ -19,8 +19,10 @@
 #include <stratosphere/pm/pm_types.hpp>
 #include <stratosphere/sf.hpp>
 
-#define AMS_PM_I_BOOT_MODE_INTERFACE_INTERFACE_INFO(C, H)                            \
-    AMS_SF_METHOD_INFO(C, H, 0, void, GetBootMode,        (sf::Out<u32> out), (out)) \
-    AMS_SF_METHOD_INFO(C, H, 1, void, SetMaintenanceBoot, (),                 ())
+#define AMS_PM_I_BOOT_MODE_INTERFACE_INTERFACE_INFO(C, H)                              \
+    AMS_SF_METHOD_INFO(C, H, 0, void,   GetBootMode,        (sf::Out<u32> out), (out)) \
+    AMS_SF_METHOD_INFO(C, H, 1, void,   SetMaintenanceBoot, (),                 ())    \
+    AMS_SF_METHOD_INFO(C, H, 2, void,   GetUnknown,         (sf::Out<u32> out), (out)) \
+    AMS_SF_METHOD_INFO(C, H, 3, Result, SetUnknown,         (u32 val),          (val))
 
 AMS_SF_DEFINE_INTERFACE(ams::pm::impl, IBootModeInterface, AMS_PM_I_BOOT_MODE_INTERFACE_INTERFACE_INFO, 0x96D01649)
diff --git a/libraries/libvapours/include/vapours/results/pm_results.hpp b/libraries/libvapours/include/vapours/results/pm_results.hpp
index 4c9e51ad5..4e4c0e24b 100644
--- a/libraries/libvapours/include/vapours/results/pm_results.hpp
+++ b/libraries/libvapours/include/vapours/results/pm_results.hpp
@@ -27,5 +27,6 @@ namespace ams::pm {
     R_DEFINE_ERROR_RESULT(DebugHookInUse,     4);
     R_DEFINE_ERROR_RESULT(ApplicationRunning, 5);
     R_DEFINE_ERROR_RESULT(InvalidSize,        6);
+    R_DEFINE_ERROR_RESULT(Unknown7,           7);
 
 }
diff --git a/stratosphere/pm/source/pm_boot_mode_service.cpp b/stratosphere/pm/source/pm_boot_mode_service.cpp
index ff389fe75..a1a762d34 100644
--- a/stratosphere/pm/source/pm_boot_mode_service.cpp
+++ b/stratosphere/pm/source/pm_boot_mode_service.cpp
@@ -22,6 +22,7 @@ namespace ams::pm {
 
         /* Global bootmode. */
         constinit BootMode g_boot_mode = BootMode::Normal;
+        constinit u32 g_unknown = 0;
 
     }
 
@@ -47,4 +48,14 @@ namespace ams::pm {
         pm::bm::SetMaintenanceBoot();
     }
 
+    void BootModeService::GetUnknown(sf::Out<u32> out) {
+        out.SetValue(g_unknown);
+    }
+
+    Result BootModeService::SetUnknown(u32 val) {
+        R_UNLESS(val <= 3, pm::ResultUnknown7());
+        g_unknown = val;
+        R_SUCCEED();
+    }
+
 }
diff --git a/stratosphere/pm/source/pm_boot_mode_service.hpp b/stratosphere/pm/source/pm_boot_mode_service.hpp
index c650e9b47..b47536ed7 100644
--- a/stratosphere/pm/source/pm_boot_mode_service.hpp
+++ b/stratosphere/pm/source/pm_boot_mode_service.hpp
@@ -22,6 +22,8 @@ namespace ams::pm {
         public:
             void GetBootMode(sf::Out<u32> out);
             void SetMaintenanceBoot();
+            void GetUnknown(sf::Out<u32> out);
+            Result SetUnknown(u32 val);
     };
     static_assert(pm::impl::IsIBootModeInterface<BootModeService>);