diff --git a/MarathonRecomp/kernel/heap.cpp b/MarathonRecomp/kernel/heap.cpp
index e3330ba09..de582c27e 100644
--- a/MarathonRecomp/kernel/heap.cpp
+++ b/MarathonRecomp/kernel/heap.cpp
@@ -60,7 +60,6 @@ size_t Heap::Size(void* ptr)
 uint32_t RtlAllocateHeap(uint32_t heapHandle, uint32_t flags, uint32_t size)
 {
     void* ptr = g_userHeap.Alloc(size);
-    // printf("RtlAllocateHeap %x, heapHandle\n", ptr);
     if ((flags & 0x8) != 0)
         memset(ptr, 0, size);
 
@@ -71,7 +70,6 @@ uint32_t RtlAllocateHeap(uint32_t heapHandle, uint32_t flags, uint32_t size)
 uint32_t RtlReAllocateHeap(uint32_t heapHandle, uint32_t flags, uint32_t memoryPointer, uint32_t size)
 {
     void* ptr = g_userHeap.Alloc(size);
-    // printf("RtlReAllocateHeap %x\n", ptr);
     if ((flags & 0x8) != 0)
         memset(ptr, 0, size);
 
@@ -88,7 +86,6 @@ uint32_t RtlReAllocateHeap(uint32_t heapHandle, uint32_t flags, uint32_t memoryP
 
 uint32_t RtlFreeHeap(uint32_t heapHandle, uint32_t flags, uint32_t memoryPointer)
 {
-    // printf("RtlFreeHeap\n");
     if (memoryPointer != NULL)
         g_userHeap.Free(g_memory.Translate(memoryPointer));
 
@@ -97,7 +94,6 @@ uint32_t RtlFreeHeap(uint32_t heapHandle, uint32_t flags, uint32_t memoryPointer
 
 uint32_t RtlSizeHeap(uint32_t heapHandle, uint32_t flags, uint32_t memoryPointer)
 {
-    // printf("RtlSizeHeap\n");
     if (memoryPointer != NULL)
         return (uint32_t)g_userHeap.Size(g_memory.Translate(memoryPointer));
 
@@ -110,7 +106,6 @@ uint32_t XAllocMem(uint32_t size, uint32_t flags)
         g_userHeap.AllocPhysical(size, (1ull << ((flags >> 24) & 0xF))) :
         g_userHeap.Alloc(size);
 
-    // printf("XAllocMem %x (size: %x)\n", ptr, size);
     if ((flags & 0x40000000) != 0)
         memset(ptr, 0, size);
 
@@ -120,40 +115,25 @@ uint32_t XAllocMem(uint32_t size, uint32_t flags)
 
 void XFreeMem(uint32_t baseAddress, uint32_t flags)
 {
-    // printf("XFreeMem %x\n", baseAddress);
     if (baseAddress != NULL)
-    {
         g_userHeap.Free(g_memory.Translate(baseAddress));
-    }
-    else
-    {
-        printf("XFreeMem baseAddress is null %x\n", baseAddress);
-        // __builtin_trap();
-    }
 }
 
 uint32_t XVirtualAlloc(void *lpAddress, unsigned int dwSize, unsigned int flAllocationType, unsigned int flProtect)
 {
-    if (lpAddress != nullptr)
-    {
-        printf("XVirtualAlloc lpAddress is not null %p\n", lpAddress);
-        return 0;
-    }
-    uint32_t addr = g_memory.MapVirtual(g_userHeap.Alloc(dwSize));
-    printf("XVirtualAlloc %x\n", addr);
-    return addr;
+    assert(!lpAddress);
+    return g_memory.MapVirtual(g_userHeap.Alloc(dwSize));
 }
 
 uint32_t XVirtualFree(uint32_t lpAddress, unsigned int dwSize, unsigned int dwFreeType)
 {
-    printf("XVirtualFree %x\n", lpAddress);
     if ((dwFreeType & 0x8000) != 0 && dwSize)
-    {
-        return 0;
-    }
+        return FALSE;
+
     if (lpAddress)
         g_userHeap.Free(g_memory.Translate(lpAddress));
-    return 1;
+
+    return TRUE;
 }
 
 GUEST_FUNCTION_HOOK(sub_82915668, XVirtualAlloc);
diff --git a/MarathonRecomp/kernel/imports.cpp b/MarathonRecomp/kernel/imports.cpp
index beebbddec..82693f353 100644
--- a/MarathonRecomp/kernel/imports.cpp
+++ b/MarathonRecomp/kernel/imports.cpp
@@ -19,7 +19,7 @@
 #include <ntstatus.h>
 #endif
 
-std::vector<uint32_t> g_doNotDestroyHandles{};
+std::unordered_map<uint32_t, uint32_t> g_handleDuplicates{};
 
 struct Event final : KernelObject, HostObject<XKEVENT>
 {
@@ -336,7 +336,6 @@ uint32_t XGetAVPack()
 
 void XamLoaderTerminateTitle()
 {
-    printf("XamLoaderTerminateTitle\n");
     LOG_UTILITY("!!! STUB !!!");
 }
 
@@ -376,7 +375,7 @@ uint32_t NtCreateFile
     uint32_t CreateOptions
 )
 {
-    printf("NtCreateFile\n");
+    LOG_UTILITY("!!! STUB !!!");
     return 0;
 }
 
@@ -387,10 +386,13 @@ uint32_t NtClose(uint32_t handle)
 
     if (IsKernelObject(handle))
     {
-        auto it = std::find(g_doNotDestroyHandles.begin(), g_doNotDestroyHandles.end(), handle);
-        if (it == g_doNotDestroyHandles.end()) {
+        // If the handle was duplicated, just decrement the duplication count. Otherwise, delete the object.
+        const auto& it = g_handleDuplicates.find(handle);
+        if (it == g_handleDuplicates.end() || it->second == 0)
             DestroyKernelObject(handle);
-        }
+        else if (--it->second == 0)
+            g_handleDuplicates.erase(it);
+
         return 0;
     }
     else
@@ -432,6 +434,9 @@ uint32_t XamLoaderSetLaunchData()
 
 uint32_t NtWaitForSingleObjectEx(uint32_t Handle, uint32_t WaitMode, uint32_t Alertable, be<int64_t>* Timeout)
 {
+    if (Handle == GUEST_INVALID_HANDLE_VALUE)
+        return 0xFFFFFFFF;
+
     uint32_t timeout = GuestTimeoutToMilliseconds(Timeout);
     // assert(timeout == 0 || timeout == INFINITE);
 
@@ -555,11 +560,29 @@ void __C_specific_handler_x()
     LOG_UTILITY("!!! STUB !!!");
 }
 
-void RtlNtStatusToDosError(int Status)
+uint32_t RtlNtStatusToDosError(uint32_t Status)
 {
-    LOG_UTILITY("!!! STUB !!!");
-    printf("RtlNtStatusToDosError: %x\n", Status);
-    // __builtin_trap();
+    // See https://github.com/wine-mirror/wine/blob/master/dlls/ntdll/error.c#L47-L64
+    if (Status == 0 || (Status & 0x20000000) != 0)
+        return Status;
+
+    if ((Status & 0xF0000000) == 0xD0000000)
+        Status &= ~0x10000000;
+
+    const uint32_t hi = (Status >> 16) & 0xFFFF;
+    if (hi == 0x8007 || hi == 0xC001 || hi == 0xC007)
+        return Status & 0xFFFF;
+
+    switch (Status)
+    {
+    case STATUS_NOT_IMPLEMENTED:
+        return ERROR_CALL_NOT_IMPLEMENTED;
+    case STATUS_SEMAPHORE_LIMIT_EXCEEDED:
+        return ERROR_TOO_MANY_POSTS;
+    default:
+        LOGF_WARNING("Unimplemented NtStatus translation: {:#08x}", Status);
+        return Status;
+    }
 }
 
 void XexGetProcedureAddress()
@@ -642,20 +665,28 @@ void NtReadFile()
     LOG_UTILITY("!!! STUB !!!");
 }
 
-int NtDuplicateObject(uint32_t sourceHandle, be<uint32_t>* targetHandle, uint32_t options)
+uint32_t NtDuplicateObject(uint32_t SourceHandle, be<uint32_t>* TargetHandle, uint32_t Options)
 {
-    auto obj = GetKernelObject(sourceHandle);
-    // HACK: Duplicating handle doesn't supported now, so we just these handles to array to ignore of closing these handles
-    printf("NtDuplicateObject: %x %x %d, obj: %x\n", sourceHandle, targetHandle, options, obj);
-    auto it = std::find(g_doNotDestroyHandles.begin(), g_doNotDestroyHandles.end(), sourceHandle);
-    if (it == g_doNotDestroyHandles.end()) {
-        g_doNotDestroyHandles.push_back(sourceHandle);
+    if (SourceHandle == GUEST_INVALID_HANDLE_VALUE)
+        return 0xFFFFFFFF;
+
+    if (IsKernelObject(SourceHandle))
+    {
+        // Increment handle duplicate count.
+        const auto& it = g_handleDuplicates.find(SourceHandle);
+        if (it != g_handleDuplicates.end())
+            ++it->second;
+        else
+            g_handleDuplicates[SourceHandle] = 1;
+
+        *TargetHandle = SourceHandle;
+        return 0;
+    }
+    else
+    {
+        assert(false && "Unrecognized kernel object.");
+        return 0xFFFFFFFF;
     }
-    if (!obj) return -1;
-    uint32_t newHandle = 0;
-    newHandle = sourceHandle;
-    *targetHandle = newHandle;
-    return 0;
 }
 
 void NtAllocateVirtualMemory()
@@ -758,13 +789,11 @@ void RtlEnterCriticalSection(XRTL_CRITICAL_SECTION* cs)
 
 void RtlImageXexHeaderField()
 {
-    printf("RtlImageXexHeaderField\n");
     LOG_UTILITY("!!! STUB !!!");
 }
 
 void HalReturnToFirmware()
 {
-    printf("HalReturnToFirmware\n");
     LOG_UTILITY("!!! STUB !!!");
 }
 
@@ -909,7 +938,7 @@ void sprintf_x()
 
 int32_t ExRegisterTitleTerminateNotification(uint32_t* reg, uint32_t create)
 {
-    printf("ExRegisterTitleTerminateNotification: %x %d\n", reg, create);
+    LOG_UTILITY("!!! STUB !!!");
     return 0;
 }
 
@@ -1111,7 +1140,6 @@ uint32_t KeTlsGetValue(uint32_t dwTlsIndex)
 
 uint32_t KeTlsSetValue(uint32_t dwTlsIndex, uint32_t lpTlsValue)
 {
-    printf("KeTlsSetValue\n");
     KeTlsGetValueRef(dwTlsIndex) = lpTlsValue;
     return TRUE;
 }
diff --git a/MarathonRecomp/kernel/io/file_system.cpp b/MarathonRecomp/kernel/io/file_system.cpp
index fa0a25d82..c9a8af4fb 100644
--- a/MarathonRecomp/kernel/io/file_system.cpp
+++ b/MarathonRecomp/kernel/io/file_system.cpp
@@ -91,7 +91,6 @@ FileHandle* XCreateFileA
     uint32_t dwFlagsAndAttributes
 )
 {
-    printf("XCreateFileA %s\n", lpFileName);
     assert(((dwDesiredAccess & ~(GENERIC_READ | GENERIC_WRITE | FILE_READ_DATA)) == 0) && "Unknown desired access bits.");
     assert(((dwShareMode & ~(FILE_SHARE_READ | FILE_SHARE_WRITE)) == 0) && "Unknown share mode bits.");
     assert(((dwCreationDisposition & ~(CREATE_NEW | CREATE_ALWAYS)) == 0) && "Unknown creation disposition bits.");
@@ -148,7 +147,6 @@ FileHandle* XCreateFileA
 
 static uint32_t XGetFileSizeA(FileHandle* hFile, be<uint32_t>* lpFileSizeHigh)
 {
-    printf("XGetFileSizeA %x\n", hFile);
     std::error_code ec;
     auto fileSize = std::filesystem::file_size(hFile->path, ec);
     if (!ec)
@@ -190,7 +188,6 @@ uint32_t XReadFile
     XOVERLAPPED* lpOverlapped
 )
 {
-    // printf("XReadFile %x %d\n", hFile, nNumberOfBytesToRead);
     uint32_t result = FALSE;
     if (lpOverlapped != nullptr)
     {
@@ -248,11 +245,6 @@ uint32_t XSetFilePointer(FileHandle* hFile, int32_t lDistanceToMove, be<int32_t>
         break;
     }
 
-    // if (!hFile) {
-    printf("XSetFilePointer %x %d %d %d %d\n", hFile, lDistanceToMove, distanceToMoveHigh, dwMoveMethod, streamSeekDir);
-    //     return INVALID_SET_FILE_POINTER;
-    // }
-
     hFile->stream.clear();
     hFile->stream.seekg(streamOffset, streamSeekDir);
     if (hFile->stream.bad())
@@ -263,7 +255,7 @@ uint32_t XSetFilePointer(FileHandle* hFile, int32_t lDistanceToMove, be<int32_t>
     std::streampos streamPos = hFile->stream.tellg();
     if (lpDistanceToMoveHigh != nullptr)
         *lpDistanceToMoveHigh = int32_t(streamPos >> 32U);
-    printf("XSetFilePointer streamPos: %d\n", streamPos);
+
     return uint32_t(streamPos);
 }
 
diff --git a/MarathonRecomp/kernel/xam.cpp b/MarathonRecomp/kernel/xam.cpp
index 59570162b..eac6f6b38 100644
--- a/MarathonRecomp/kernel/xam.cpp
+++ b/MarathonRecomp/kernel/xam.cpp
@@ -314,7 +314,6 @@ uint32_t XamContentCreateEx(uint32_t dwUserIndex, const char* szRootName, const
     uint32_t dwContentFlags, be<uint32_t>* pdwDisposition, be<uint32_t>* pdwLicenseMask,
     uint32_t dwFileCacheSize, uint64_t uliContentSize, PXXOVERLAPPED pOverlapped)
 {
-    printf("XamContentCreateEx: %d, %s %d\n", dwUserIndex, szRootName, dwContentFlags);
     const auto& registry = gContentRegistry[pContentData->dwContentType - 1];
     const auto exists = registry.contains(StringHash(pContentData->szFileName));
     const auto mode = dwContentFlags & 0xF;
diff --git a/MarathonRecomp/kernel/xdm.h b/MarathonRecomp/kernel/xdm.h
index b001970bf..c477df607 100644
--- a/MarathonRecomp/kernel/xdm.h
+++ b/MarathonRecomp/kernel/xdm.h
@@ -14,8 +14,9 @@
 #define STATUS_SUCCESS             0x00000000
 #define STATUS_WAIT_0              0x00000000
 #define STATUS_USER_APC            0x000000C0
-#define STATUS_SEMAPHORE_LIMIT_EXCEEDED             0xC0000047 
 #define STATUS_TIMEOUT             0x00000102
+#define STATUS_NOT_IMPLEMENTED     0xC0000002
+#define STATUS_SEMAPHORE_LIMIT_EXCEEDED             0xC0000047
 #define STATUS_FAIL_CHECK          0xC0000229
 #define INFINITE                   0xFFFFFFFF
 #define FILE_ATTRIBUTE_DIRECTORY   0x00000010  
@@ -40,7 +41,9 @@
 #define ERROR_PATH_NOT_FOUND       0x3
 #define ERROR_ACCESS_DENIED        0x5
 #define ERROR_FILE_EXISTS          0x50
+#define ERROR_CALL_NOT_IMPLEMENTED 0x78
 #define ERROR_BAD_ARGUMENTS        0xA0
+#define ERROR_TOO_MANY_POSTS       0x12A
 #define ERROR_DEVICE_NOT_CONNECTED 0x48F
 #define PAGE_READWRITE             0x04