diff --git a/src/core/file_sys/directories/base_directory.h b/src/core/file_sys/directories/base_directory.h
index 8900ac32b..b412865a2 100644
--- a/src/core/file_sys/directories/base_directory.h
+++ b/src/core/file_sys/directories/base_directory.h
@@ -36,6 +36,18 @@ public:
         return ORBIS_KERNEL_ERROR_EBADF;
     }
 
+    virtual s64 write(const void* buf, u64 nbytes) {
+        return ORBIS_KERNEL_ERROR_EBADF;
+    }
+
+    virtual s64 writev(const Libraries::Kernel::OrbisKernelIovec* iov, s32 iovcnt) {
+        return ORBIS_KERNEL_ERROR_EBADF;
+    }
+
+    virtual s64 pwritev(const Libraries::Kernel::OrbisKernelIovec* iov, s32 iovcnt, s64 offset) {
+        return ORBIS_KERNEL_ERROR_EBADF;
+    }
+
     virtual s64 lseek(s64 offset, s32 whence) {
         return ORBIS_KERNEL_ERROR_EBADF;
     }
diff --git a/src/core/libraries/fiber/fiber.cpp b/src/core/libraries/fiber/fiber.cpp
index 7d35add4e..776792041 100644
--- a/src/core/libraries/fiber/fiber.cpp
+++ b/src/core/libraries/fiber/fiber.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "fiber.h"
@@ -6,8 +6,8 @@
 #include "common/elf_info.h"
 #include "common/logging/log.h"
 #include "core/libraries/fiber/fiber_error.h"
+#include "core/libraries/kernel/threads/pthread.h"
 #include "core/libraries/libs.h"
-#include "core/tls.h"
 
 namespace Libraries::Fiber {
 
@@ -20,7 +20,7 @@ static constexpr u64 kFiberStackSizeCheck = 0xdeadbeefdeadbeef;
 static std::atomic<u32> context_size_check = false;
 
 OrbisFiberContext* GetFiberContext() {
-    return Core::GetTcbBase()->tcb_fiber;
+    return Libraries::Kernel::g_curthread->tcb->tcb_fiber;
 }
 
 extern "C" s32 PS4_SYSV_ABI _sceFiberSetJmp(OrbisFiberContext* ctx) asm("_sceFiberSetJmp");
@@ -269,7 +269,7 @@ s32 PS4_SYSV_ABI sceFiberRunImpl(OrbisFiber* fiber, void* addr_context, u64 size
         return ORBIS_FIBER_ERROR_INVALID;
     }
 
-    Core::Tcb* tcb = Core::GetTcbBase();
+    Core::Tcb* tcb = Libraries::Kernel::g_curthread->tcb;
     if (tcb->tcb_fiber) {
         return ORBIS_FIBER_ERROR_PERMISSION;
     }
diff --git a/src/core/libraries/kernel/file_system.cpp b/src/core/libraries/kernel/file_system.cpp
index 7ded1f33e..b4c342f18 100644
--- a/src/core/libraries/kernel/file_system.cpp
+++ b/src/core/libraries/kernel/file_system.cpp
@@ -311,6 +311,9 @@ s64 PS4_SYSV_ABI write(s32 fd, const void* buf, u64 nbytes) {
     } else if (file->type == Core::FileSys::FileType::Socket) {
         // Socket functions handle errnos internally.
         return file->socket->SendPacket(buf, nbytes, 0, nullptr, 0);
+    } else if (file->type == Core::FileSys::FileType::Directory) {
+        *__Error() = POSIX_EBADF;
+        return -1;
     }
 
     return file->f.WriteRaw<u8>(buf, nbytes);
@@ -405,7 +408,11 @@ s64 PS4_SYSV_ABI writev(s32 fd, const OrbisKernelIovec* iov, s32 iovcnt) {
             return -1;
         }
         return result;
+    } else if (file->type == Core::FileSys::FileType::Directory) {
+        *__Error() = POSIX_EBADF;
+        return -1;
     }
+
     s64 total_written = 0;
     for (s32 i = 0; i < iovcnt; i++) {
         total_written += file->f.WriteRaw<u8>(iov[i].iov_base, iov[i].iov_len);
@@ -1047,7 +1054,11 @@ s64 PS4_SYSV_ABI posix_pwritev(s32 fd, const OrbisKernelIovec* iov, s32 iovcnt,
             return -1;
         }
         return result;
+    } else if (file->type == Core::FileSys::FileType::Directory) {
+        *__Error() = POSIX_EBADF;
+        return -1;
     }
+
     const s64 pos = file->f.Tell();
     SCOPE_EXIT {
         file->f.Seek(pos);
diff --git a/src/core/linker.cpp b/src/core/linker.cpp
index ac6b37769..b7c9a2895 100644
--- a/src/core/linker.cpp
+++ b/src/core/linker.cpp
@@ -368,7 +368,7 @@ bool Linker::Resolve(const std::string& name, Loader::SymbolType sym_type, Modul
 void* Linker::TlsGetAddr(u64 module_index, u64 offset) {
     std::scoped_lock lk{mutex};
 
-    DtvEntry* dtv_table = GetTcbBase()->tcb_dtv;
+    DtvEntry* dtv_table = Libraries::Kernel::g_curthread->tcb->tcb_dtv;
     if (dtv_table[0].counter != dtv_generation_counter) {
         // Generation counter changed, a dynamic module was either loaded or unloaded.
         const u32 old_num_dtvs = dtv_table[1].counter;
@@ -381,7 +381,7 @@ void* Linker::TlsGetAddr(u64 module_index, u64 offset) {
         delete[] dtv_table;
 
         // Update TCB pointer.
-        GetTcbBase()->tcb_dtv = new_dtv_table;
+        Libraries::Kernel::g_curthread->tcb->tcb_dtv = new_dtv_table;
         dtv_table = new_dtv_table;
     }
 
diff --git a/src/core/tls.cpp b/src/core/tls.cpp
index 2f7e1a1fd..bcefd6f25 100644
--- a/src/core/tls.cpp
+++ b/src/core/tls.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <mutex>
@@ -46,10 +46,6 @@ void SetTcbBase(void* image_address) {
     ASSERT(result != 0);
 }
 
-Tcb* GetTcbBase() {
-    return reinterpret_cast<Tcb*>(TlsGetValue(GetTcbKey()));
-}
-
 #elif defined(__APPLE__) && defined(ARCH_X86_64)
 
 // Apple x86_64
@@ -149,12 +145,6 @@ void SetTcbBase(void* image_address) {
                "Failed to store thread LDT page pointer: {}", errno);
 }
 
-Tcb* GetTcbBase() {
-    Tcb* tcb;
-    asm volatile("mov %%fs:0x0, %0" : "=r"(tcb));
-    return tcb;
-}
-
 #elif defined(ARCH_X86_64)
 
 // Other POSIX x86_64
@@ -164,13 +154,6 @@ void SetTcbBase(void* image_address) {
     ASSERT_MSG(ret == 0, "Failed to set GS base: errno {}", errno);
 }
 
-Tcb* GetTcbBase() {
-    void* tcb = nullptr;
-    const int ret = syscall(SYS_arch_prctl, ARCH_GET_GS, &tcb);
-    ASSERT_MSG(ret == 0, "Failed to get GS base: errno {}", errno);
-    return static_cast<Tcb*>(tcb);
-}
-
 #else
 
 // POSIX non-x86_64
@@ -193,10 +176,6 @@ void SetTcbBase(void* image_address) {
     ASSERT(pthread_setspecific(GetTcbKey(), image_address) == 0);
 }
 
-Tcb* GetTcbBase() {
-    return static_cast<Tcb*>(pthread_getspecific(GetTcbKey()));
-}
-
 #endif
 
 thread_local std::once_flag init_tls_flag;
diff --git a/src/core/tls.h b/src/core/tls.h
index 787744cd3..6be9752b0 100644
--- a/src/core/tls.h
+++ b/src/core/tls.h
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
@@ -36,9 +36,6 @@ u32 GetTcbKey();
 /// Sets the data pointer to the TCB block.
 void SetTcbBase(void* image_address);
 
-/// Retrieves Tcb structure for the calling thread.
-Tcb* GetTcbBase();
-
 /// Makes sure TLS is initialized for the thread before entering guest.
 void EnsureThreadInitialized();
 
diff --git a/src/emulator.cpp b/src/emulator.cpp
index ad407f9b6..fb187cfae 100644
--- a/src/emulator.cpp
+++ b/src/emulator.cpp
@@ -58,10 +58,11 @@ Frontend::WindowSDL* g_window = nullptr;
 namespace Core {
 
 Emulator::Emulator() {
-    // Initialize NT API functions and set high priority
+    // Initialize NT API functions, set high priority and disable WER
 #ifdef _WIN32
     Common::NtApi::Initialize();
     SetPriorityClass(GetCurrentProcess(), ABOVE_NORMAL_PRIORITY_CLASS);
+    SetErrorMode(SetErrorMode(0) | SEM_NOGPFAULTERRORBOX);
     // need to init this in order for winsock2 to work
     WORD versionWanted = MAKEWORD(2, 2);
     WSADATA wsaData;