diff --git a/core/libs/prx/libkernel/Pthread/Posix/Thread.cpp b/core/libs/prx/libkernel/Pthread/Posix/Thread.cpp
index 89e978d708..4fff7c3a22 100644
--- a/core/libs/prx/libkernel/Pthread/Posix/Thread.cpp
+++ b/core/libs/prx/libkernel/Pthread/Posix/Thread.cpp
@@ -126,15 +126,19 @@ int APS5_VABI rtprio_thread_nid_postfix(int function, int lwpid, GuestRtPrio* pr
     int schedPriority = self->priority.load(std::memory_order_relaxed);
     const bool other = lwpid != 0 && static_cast<std::int64_t>(lwpid) != static_cast<std::int64_t>(self->tid);
     if (other && !GetLiveGuestThreadSched_nid_no_patch(lwpid, policy, schedPriority)) return fail(GuestEsrch);
+    GuestRtPrio requested{};
+    if (function == Set && !GuestCopyIn_nid_no_patch(&requested, priority, sizeof(requested))) return fail(GuestEfault);
     const bool realTime = policy == GuestSchedFifo || policy == GuestSchedRr;
     if (function == Lookup) {
-        priority->type = realTime ? (policy == GuestSchedFifo ? Fifo : Realtime) : Normal;
-        priority->prio = realTime ? static_cast<std::uint16_t>(schedPriority) : 0;
+        GuestRtPrio current{};
+        current.type = realTime ? (policy == GuestSchedFifo ? Fifo : Realtime) : Normal;
+        current.prio = realTime ? static_cast<std::uint16_t>(schedPriority) : 0;
+        if (!GuestCopyOut_nid_no_patch(priority, &current, sizeof(current))) return fail(GuestEfault);
         return 0;
     }
     if (other) NotImplemented_nid_no_patch("rtprio_thread: a thread other than the calling one");
     if (realTime) NotImplemented_nid_no_patch("rtprio_thread: a guest thread's real-time class");
-    if (priority->type == Normal && priority->prio == 0) return 0;
+    if (requested.type == Normal && requested.prio == 0) return 0;
     NotImplemented_nid_no_patch("rtprio_thread: a real-time priority change");
 }
 
diff --git a/core/libs/prx/libkernel_sys/Export.cpp b/core/libs/prx/libkernel_sys/Export.cpp
index 1195d93f25..de60e1a45c 100644
--- a/core/libs/prx/libkernel_sys/Export.cpp
+++ b/core/libs/prx/libkernel_sys/Export.cpp
@@ -986,9 +986,8 @@ int APS5_VABI sched_rr_get_interval_nid_postfix(int pid, KernelTimespec* interva
     constexpr int GuestEsrch = 3;
     const int self = getpid_nid_postfix();
     if (pid != 0 && pid != self) return static_cast<int>(Fail(GuestEsrch));
-    if (interval == nullptr) return static_cast<int>(Fail(GuestEfault));
-    interval->tv_sec = 0;
-    interval->tv_nsec = 94000000;
+    const KernelTimespec quantum{0, 94000000};
+    if (interval == nullptr || !GuestCopyOut_nid_no_patch(interval, &quantum, sizeof(quantum))) return static_cast<int>(Fail(GuestEfault));
     return 0;
 }
 
diff --git a/core/libs/tests/GuestRtprioThread.cpp b/core/libs/tests/GuestRtprioThread.cpp
index 0d44857120..a9ec33d1f7 100644
--- a/core/libs/tests/GuestRtprioThread.cpp
+++ b/core/libs/tests/GuestRtprioThread.cpp
@@ -92,6 +92,17 @@ int main() {
     CheckThread(GUEST_SCHED_FIFO, 256, RTP_PRIO_FIFO);
     Require(LookupError(2, 0, &self) == GUEST_ESRCH);
     Require(LookupError(RTP_LOOKUP, 0, nullptr) == GUEST_EFAULT);
+    auto* unmapped = reinterpret_cast<GuestRtPrio*>(std::uintptr_t{0x10});
+    Require(LookupError(RTP_LOOKUP, 0, unmapped) == GUEST_EFAULT);
+    Require(LookupError(RTP_SET, 0, unmapped) == GUEST_EFAULT);
+    Require(LookupError(RTP_SET, 999999, unmapped) == GUEST_ESRCH);
+    void* page = nullptr;
+    Require(sceKernelMapFlexibleMemory(&page, 0x4000, 3, 0) == 0 && page != nullptr);
+    auto* readOnly = static_cast<GuestRtPrio*>(page);
+    *readOnly = {7, 7};
+    Require(sceKernelMprotect(page, 0x4000, 1) == 0);
+    Require(LookupError(RTP_LOOKUP, 0, readOnly) == GUEST_EFAULT);
+    Require(readOnly->type == 7 && readOnly->prio == 7);
     Require(LookupError(RTP_LOOKUP, 1, &self) == GUEST_ESRCH);
     Require(LookupError(RTP_LOOKUP, 999999, &self) == GUEST_ESRCH);
     bool threw = false;
diff --git a/core/libs/tests/GuestSchedPriority.cpp b/core/libs/tests/GuestSchedPriority.cpp
index 27f7e23a90..8aaec24a56 100644
--- a/core/libs/tests/GuestSchedPriority.cpp
+++ b/core/libs/tests/GuestSchedPriority.cpp
@@ -54,6 +54,16 @@ int main() {
     Require(sched_rr_get_interval_nid_postfix(self + 1, &interval) == -1 && *__error_nid_postfix() == 3);
     *__error_nid_postfix() = 0;
     Require(sched_rr_get_interval_nid_postfix(0, nullptr) == -1 && *__error_nid_postfix() == 14);
+    *__error_nid_postfix() = 0;
+    Require(sched_rr_get_interval_nid_postfix(0, reinterpret_cast<KernelTimespec*>(std::uintptr_t{0x10})) == -1 && *__error_nid_postfix() == 14);
+    *__error_nid_postfix() = 0;
+    Require(sched_rr_get_interval_nid_postfix(-1, reinterpret_cast<KernelTimespec*>(std::uintptr_t{0x10})) == -1 && *__error_nid_postfix() == 3);
+    void* page = nullptr;
+    Require(sceKernelMapFlexibleMemory(&page, 0x4000, 3, 0) == 0 && page != nullptr);
+    Require(sceKernelMprotect(page, 0x4000, 1) == 0);
+    *__error_nid_postfix() = 0;
+    Require(sched_rr_get_interval_nid_postfix(0, static_cast<KernelTimespec*>(page)) == -1 && *__error_nid_postfix() == 14);
+    Require(static_cast<KernelTimespec*>(page)->tv_nsec == 0);
     for (int policy : {1, 3}) {
         Require(sched_get_priority_max_nid_postfix(policy) == 767);
         Require(sched_get_priority_min_nid_postfix(policy) == 256);