diff --git a/src/xenia/kernel/xboxkrnl/xboxkrnl_threading.cc b/src/xenia/kernel/xboxkrnl/xboxkrnl_threading.cc
index 42292895b..29b064841 100644
--- a/src/xenia/kernel/xboxkrnl/xboxkrnl_threading.cc
+++ b/src/xenia/kernel/xboxkrnl/xboxkrnl_threading.cc
@@ -222,13 +222,23 @@ void KeSetCurrentStackPointers(lpvoid_t stack_ptr,
 }
 DECLARE_XBOXKRNL_EXPORT1(KeSetCurrentStackPointers, kThreading, kImplemented);
 
-dword_result_t KeSetAffinityThread(lpvoid_t thread_ptr, dword_t affinity) {
-  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
-  if (thread) {
-    thread->SetAffinity(affinity);
+dword_result_t KeSetAffinityThread(lpvoid_t thread_ptr, dword_t affinity,
+                                   lpdword_t previous_affinity_ptr) {
+  // Xbox 360 uses additional parameter (in comparation to NT equivalent)
+  // which is used only for returning previous thread affinity. (Based on code
+  // dissasembly)
+  if (!affinity) {
+    return X_STATUS_INVALID_PARAMETER;
   }
 
-  return (uint32_t)affinity;
+  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
+  if (thread) {
+    if (previous_affinity_ptr) {
+      *previous_affinity_ptr = 1 << thread->active_cpu();
+    }
+    thread->SetAffinity(affinity);
+  }
+  return X_STATUS_SUCCESS;
 }
 DECLARE_XBOXKRNL_EXPORT1(KeSetAffinityThread, kThreading, kImplemented);
 
diff --git a/src/xenia/kernel/xthread.cc b/src/xenia/kernel/xthread.cc
index 458d7a592..1e4753053 100644
--- a/src/xenia/kernel/xthread.cc
+++ b/src/xenia/kernel/xthread.cc
@@ -205,6 +205,7 @@ void XThread::InitializeGuestObject() {
   // 0xA88 = APC
   // 0x18 = timer
   xe::store_and_swap<uint32_t>(p + 0x09C, 0xFDFFD7FF);
+  xe::store_and_swap<uint8_t>(p + 0xBF, 0);
   xe::store_and_swap<uint32_t>(p + 0x0D0, stack_base_);
   xe::store_and_swap<uint64_t>(p + 0x130, Clock::QueryGuestSystemTime());
   xe::store_and_swap<uint32_t>(p + 0x144, guest_object() + 0x144);
@@ -346,6 +347,9 @@ X_STATUS XThread::Create() {
   // Exports use this to get the kernel.
   thread_state_->context()->kernel_state = kernel_state_;
 
+  // Initialize the KTHREAD object.
+  InitializeGuestObject();
+
   X_KPCR* pcr = memory()->TranslateVirtual<X_KPCR*>(pcr_address_);
 
   pcr->tls_ptr = tls_static_address_;
@@ -355,14 +359,12 @@ X_STATUS XThread::Create() {
   pcr->stack_base_ptr = stack_base_;
   pcr->stack_end_ptr = stack_limit_;
 
+  pcr->dpc_active = 0;  // DPC active bool?
+
   uint8_t proc_mask =
       static_cast<uint8_t>(creation_params_.creation_flags >> 24);
-
-  pcr->current_cpu = GetFakeCpuNumber(proc_mask);  // Current CPU(?)
-  pcr->dpc_active = 0;                             // DPC active bool?
-
-  // Initialize the KTHREAD object.
-  InitializeGuestObject();
+  // Assign cpu core used by thread on guest side
+  SetAffinity(1 << GetFakeCpuNumber(proc_mask));
 
   // Always retain when starting - the thread owns itself until exited.
   RetainHandle();
@@ -714,7 +716,7 @@ void XThread::SetAffinity(uint32_t affinity) {
     XELOGW("Too few processors - scheduling will be wonky");
   }
   SetActiveCpu(GetFakeCpuNumber(affinity));
-  affinity_ = affinity;
+
   if (!cvars::ignore_thread_affinities) {
     thread_->set_affinity_mask(affinity);
   }
@@ -729,6 +731,12 @@ void XThread::SetActiveCpu(uint32_t cpu_index) {
   assert_true(cpu_index < 6);
   uint8_t* pcr = memory()->TranslateVirtual(pcr_address_);
   xe::store_and_swap<uint8_t>(pcr + 0x10C, cpu_index);
+
+  if (is_guest_thread()) {
+    X_KTHREAD* thread_object =
+        memory()->TranslateVirtual<X_KTHREAD*>(guest_object());
+    thread_object->current_cpu = cpu_index;
+  }
 }
 
 bool XThread::GetTLSValue(uint32_t slot, uint32_t* value_out) {
diff --git a/src/xenia/kernel/xthread.h b/src/xenia/kernel/xthread.h
index 2b6518703..de813bb49 100644
--- a/src/xenia/kernel/xthread.h
+++ b/src/xenia/kernel/xthread.h
@@ -88,7 +88,8 @@ struct X_KTHREAD {
   char unk_10[0xAC];             // 0x10
   uint8_t suspend_count;         // 0xBC
   uint8_t unk_BD;                // 0xBD
-  uint16_t unk_BE;               // 0xBE
+  uint8_t unk_BE;                // 0xBE
+  uint8_t current_cpu;           // 0xBF
   char unk_C0[0x70];             // 0xC0
   xe::be<uint64_t> create_time;  // 0x130
   xe::be<uint64_t> exit_time;    // 0x138
@@ -165,7 +166,6 @@ class XThread : public XObject, public cpu::Thread {
   int32_t priority() const { return priority_; }
   int32_t QueryPriority();
   void SetPriority(int32_t increment);
-  uint32_t affinity() const { return affinity_; }
   void SetAffinity(uint32_t affinity);
   uint32_t active_cpu() const;
   void SetActiveCpu(uint32_t cpu_index);
@@ -220,7 +220,6 @@ class XThread : public XObject, public cpu::Thread {
   bool running_ = false;
 
   int32_t priority_ = 0;
-  uint32_t affinity_ = 0;
 
   xe::global_critical_region global_critical_region_;
   std::atomic<uint32_t> irql_ = {0};