diff --git a/dlls/ntdll/unix/server.c b/dlls/ntdll/unix/server.c
index d867a7fb462..0fd8f537b25 100644
--- a/dlls/ntdll/unix/server.c
+++ b/dlls/ntdll/unix/server.c
@@ -1486,7 +1486,7 @@ void CDECL server_init_process_done( void *relay )
     SERVER_END_REQ;
 
     assert( !status );
-    signal_start_thread( entry, peb, suspend, relay, NtCurrentTeb() );
+    signal_start_thread( entry, peb, suspend, relay, pLdrInitializeThunk, NtCurrentTeb() );
 }
 
 
diff --git a/dlls/ntdll/unix/signal_arm.c b/dlls/ntdll/unix/signal_arm.c
index e619dbd9755..fe54b9d68fd 100644
--- a/dlls/ntdll/unix/signal_arm.c
+++ b/dlls/ntdll/unix/signal_arm.c
@@ -906,10 +906,10 @@ static void init_thread_context( CONTEXT *context, LPTHREAD_START_ROUTINE entry,
 
 
 /***********************************************************************
- *           attach_thread
+ *           get_initial_context
  */
-PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
-                                        BOOL suspend, void *relay )
+PCONTEXT DECLSPEC_HIDDEN get_initial_context( LPTHREAD_START_ROUTINE entry, void *arg,
+                                              BOOL suspend, void *relay )
 {
     CONTEXT *ctx;
 
@@ -929,7 +929,6 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
     }
     pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
     ctx->ContextFlags = CONTEXT_FULL;
-    pLdrInitializeThunk( ctx, (void **)&ctx->R0, 0, 0 );
     return ctx;
 }
 
@@ -940,22 +939,18 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
 __ASM_GLOBAL_FUNC( signal_start_thread,
                    ".arm\n\t"
                    "push {r4-r12,lr}\n\t"
+                   "ldr r5, [sp, #40]\n\t"    /* thunk */
                    /* store exit frame */
-                   "ldr r4, [sp, #40]\n\t"    /* teb */
+                   "ldr r4, [sp, #44]\n\t"    /* teb */
                    "str sp, [r4, #0x1d4]\n\t" /* teb->GdiTebBatch */
                    /* switch to thread stack */
                    "ldr r4, [r4, #4]\n\t"     /* teb->Tib.StackBase */
                    "sub sp, r4, #0x1000\n\t"
                    /* attach dlls */
-                   "bl " __ASM_NAME("attach_thread") "\n\t"
-                   "mov sp, r0\n\t"
-                   /* clear the stack */
-                   "and r0, #~0xff0\n\t"  /* round down to page size */
-                   "bl " __ASM_NAME("virtual_clear_thread_stack") "\n\t"
-                   /* switch to the initial context */
-                   "mov r1, #1\n\t"
-                   "mov r0, sp\n\t"
-                   "b " __ASM_NAME("NtContinue") )
+                   "bl " __ASM_NAME("get_initial_context") "\n\t"
+                   "add r1, r0, #4\n\t"       /* &context->R0 */
+                   "mov lr, #0\n\t"
+                   "bx r5" )
 
 
 extern void DECLSPEC_NORETURN call_thread_exit_func( int status, void (*func)(int), TEB *teb );
diff --git a/dlls/ntdll/unix/signal_arm64.c b/dlls/ntdll/unix/signal_arm64.c
index 7fe40d4ea12..7a68fa2a472 100644
--- a/dlls/ntdll/unix/signal_arm64.c
+++ b/dlls/ntdll/unix/signal_arm64.c
@@ -990,10 +990,10 @@ static void init_thread_context( CONTEXT *context, LPTHREAD_START_ROUTINE entry,
 
 
 /***********************************************************************
- *           attach_thread
+ *           get_initial_context
  */
-PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
-                                        BOOL suspend, void *relay )
+PCONTEXT DECLSPEC_HIDDEN get_initial_context( LPTHREAD_START_ROUTINE entry, void *arg,
+                                              BOOL suspend, void *relay )
 {
     CONTEXT *ctx;
 
@@ -1012,8 +1012,7 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
         init_thread_context( ctx, entry, arg, relay );
     }
     pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
-    ctx->ContextFlags = CONTEXT_FULL;
-    pLdrInitializeThunk( ctx, (void **)&ctx->u.s.X0, 0, 0 );
+    ctx->ContextFlags = CONTEXT_FULL | CONTEXT_FLOATING_POINT;
     return ctx;
 }
 
@@ -1023,43 +1022,19 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
  */
 __ASM_GLOBAL_FUNC( signal_start_thread,
                    "stp x29, x30, [sp,#-16]!\n\t"
-                   "mov x18, x4\n\t"             /* teb */
+                   "mov x19, x4\n\t"             /* thunk */
+                   "mov x18, x5\n\t"             /* teb */
                    /* store exit frame */
                    "mov x29, sp\n\t"
-                   "str x29, [x4, #0x2f0]\n\t"  /* arm64_thread_data()->exit_frame */
+                   "str x29, [x5, #0x2f0]\n\t"  /* arm64_thread_data()->exit_frame */
                    /* switch to thread stack */
-                   "ldr x5, [x4, #8]\n\t"       /* teb->Tib.StackBase */
+                   "ldr x5, [x5, #8]\n\t"       /* teb->Tib.StackBase */
                    "sub sp, x5, #0x1000\n\t"
                    /* attach dlls */
-                   "bl " __ASM_NAME("attach_thread") "\n\t"
-                   "mov sp, x0\n\t"
-                   /* clear the stack */
-                   "and x0, x0, #~0xfff\n\t"  /* round down to page size */
-                   "bl " __ASM_NAME("virtual_clear_thread_stack") "\n\t"
-                   /* switch to the initial context */
-                   "mov x0, sp\n\t"
-                   "ldp q0, q1, [x0, #0x110]\n\t"      /* context->V[0,1] */
-                   "ldp q2, q3, [x0, #0x130]\n\t"      /* context->V[2,3] */
-                   "ldp q4, q5, [x0, #0x150]\n\t"      /* context->V[4,5] */
-                   "ldp q6, q7, [x0, #0x170]\n\t"      /* context->V[6,7] */
-                   "ldp q8, q9, [x0, #0x190]\n\t"      /* context->V[8,9] */
-                   "ldp q10, q11, [x0, #0x1b0]\n\t"    /* context->V[10,11] */
-                   "ldp q12, q13, [x0, #0x1d0]\n\t"    /* context->V[12,13] */
-                   "ldp q14, q15, [x0, #0x1f0]\n\t"    /* context->V[14,15] */
-                   "ldp q16, q17, [x0, #0x210]\n\t"    /* context->V[16,17] */
-                   "ldp q18, q19, [x0, #0x230]\n\t"    /* context->V[18,19] */
-                   "ldp q20, q21, [x0, #0x250]\n\t"    /* context->V[20,21] */
-                   "ldp q22, q23, [x0, #0x270]\n\t"    /* context->V[22,23] */
-                   "ldp q24, q25, [x0, #0x290]\n\t"    /* context->V[24,25] */
-                   "ldp q26, q27, [x0, #0x2b0]\n\t"    /* context->V[26,27] */
-                   "ldp q28, q29, [x0, #0x2d0]\n\t"    /* context->V[28,29] */
-                   "ldp q30, q31, [x0, #0x2f0]\n\t"    /* context->V[30,31] */
-                   "ldr w1, [x0, #0x310]\n\t"          /* context->Fpcr */
-                   "msr fpcr, x1\n\t"
-                   "ldr w1, [x0, #0x314]\n\t"          /* context->Fpsr */
-                   "msr fpsr, x1\n\t"
-                   "mov x1, #1\n\t"
-                   "b " __ASM_NAME("NtContinue") )
+                   "bl " __ASM_NAME("get_initial_context") "\n\t"
+                   "add x1, x0, #4\n\t"        /* &context->X0 */
+                   "mov lr, #0\n\t"
+                   "br x19" )
 
 
 extern void DECLSPEC_NORETURN call_thread_exit_func( int status, void (*func)(int), TEB *teb );
diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 39c154ebbc1..a65f4d60cc7 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -2240,10 +2240,10 @@ static void init_thread_context( CONTEXT *context, LPTHREAD_START_ROUTINE entry,
 
 
 /***********************************************************************
- *           attach_thread
+ *           get_initial_context
  */
-PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
-                                        BOOL suspend, void *relay )
+PCONTEXT DECLSPEC_HIDDEN get_initial_context( LPTHREAD_START_ROUTINE entry, void *arg,
+                                              BOOL suspend, void *relay )
 {
     CONTEXT *ctx;
 
@@ -2263,7 +2263,6 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
     }
     pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
     ctx->ContextFlags = CONTEXT_FULL | CONTEXT_FLOATING_POINT | CONTEXT_EXTENDED_REGISTERS;
-    pLdrInitializeThunk( ctx, (void **)&ctx->Eax, 0, 0 );
     return ctx;
 }
 
@@ -2293,18 +2292,14 @@ __ASM_GLOBAL_FUNC( signal_start_thread,
                    "pushl 16(%ebp)\n\t"         /* suspend */
                    "pushl 12(%ebp)\n\t"         /* arg */
                    "pushl 8(%ebp)\n\t"          /* entry */
+                   "call " __ASM_NAME("get_initial_context") "\n\t"
+                   "movl %eax,(%esp)\n\t"       /* context */
+                   "leal 0xb0(%eax),%eax\n\t"   /* &context->Eax */
+                   "movl %eax,4(%esp)\n\t"
+                   "movl 24(%ebp),%edx\n\t"     /* thunk */
                    "xorl %ebp,%ebp\n\t"
-                   "call " __ASM_NAME("attach_thread") "\n\t"
-                   "movl %eax,%esi\n\t"
-                   "leal -12(%eax),%esp\n\t"
-                   /* clear the stack */
-                   "andl $~0xfff,%eax\n\t"  /* round down to page size */
-                   "movl %eax,(%esp)\n\t"
-                   "call " __ASM_NAME("virtual_clear_thread_stack") "\n\t"
-                   /* switch to the initial context */
-                   "movl $1,4(%esp)\n\t"
-                   "movl %esi,(%esp)\n\t"
-                   "call " __ASM_NAME("NtContinue") )
+                   "pushl $0\n\t"
+                   "jmp *%edx" )
 
 
 /***********************************************************************
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 6f01b76c5ae..3a929d70f11 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2467,10 +2467,10 @@ static void init_thread_context( CONTEXT *context, LPTHREAD_START_ROUTINE entry,
 
 
 /***********************************************************************
- *           attach_thread
+ *           get_initial_context
  */
-PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
-                                        BOOL suspend, void *relay )
+PCONTEXT DECLSPEC_HIDDEN get_initial_context( LPTHREAD_START_ROUTINE entry, void *arg,
+                                              BOOL suspend, void *relay )
 {
     CONTEXT *ctx;
 
@@ -2491,7 +2491,6 @@ PCONTEXT DECLSPEC_HIDDEN attach_thread( LPTHREAD_START_ROUTINE entry, void *arg,
     }
     pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
     ctx->ContextFlags = CONTEXT_FULL;
-    pLdrInitializeThunk( ctx, (void **)&ctx->Rcx, 0, 0 );
     return ctx;
 }
 
@@ -2521,19 +2520,15 @@ __ASM_GLOBAL_FUNC( signal_start_thread,
                    "movq %rsp,0x320(%rax)\n\t"      /* amd64_thread_data()->exit_frame */
                    /* switch to thread stack */
                    "movq 8(%rax),%rax\n\t"          /* NtCurrentTeb()->Tib.StackBase */
+                   "movq %r8,%rbx\n\t"              /* thunk */
                    "leaq -0x1000(%rax),%rsp\n\t"
                    /* attach dlls */
-                   "call " __ASM_NAME("attach_thread") "\n\t"
-                   "movq %rax,%rbx\n\t"
-                   "leaq -32(%rax),%rsp\n\t"
-                   /* clear the stack */
-                   "andq $~0xfff,%rax\n\t"  /* round down to page size */
-                   "movq %rax,%rdi\n\t"
-                   "call " __ASM_NAME("virtual_clear_thread_stack") "\n\t"
-                   /* switch to the initial context */
-                   "movl $1,%edx\n\t"
-                   "movq %rbx,%rcx\n\t"
-                   "call " __ASM_NAME("NtContinue") )
+                   "call " __ASM_NAME("get_initial_context") "\n\t"
+                   "movq %rax,%rcx\n\t"             /* context */
+                   "leaq 0x80(%rcx),%rdx\n\t"       /* &context->Rcx */
+                   "xorq %rax,%rax\n\t"
+                   "pushq %rax\n\t"
+                   "jmp *%rbx" )
 
 
 /***********************************************************************
diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
index cb7377017b8..28c7d816b72 100644
--- a/dlls/ntdll/unix/thread.c
+++ b/dlls/ntdll/unix/thread.c
@@ -99,7 +99,8 @@ static void start_thread( TEB *teb )
     thread_data->pthread_id = pthread_self();
     signal_init_thread( teb );
     server_init_thread( thread_data->start, &suspend );
-    signal_start_thread( thread_data->start, thread_data->param, suspend, pRtlUserThreadStart, teb );
+    signal_start_thread( thread_data->start, thread_data->param, suspend,
+                         pRtlUserThreadStart, pLdrInitializeThunk, teb );
 }
 
 
diff --git a/dlls/ntdll/unix/unix_private.h b/dlls/ntdll/unix/unix_private.h
index 397211957bd..f7619964a2d 100644
--- a/dlls/ntdll/unix/unix_private.h
+++ b/dlls/ntdll/unix/unix_private.h
@@ -231,7 +231,7 @@ extern void signal_free_thread( TEB *teb ) DECLSPEC_HIDDEN;
 extern void signal_init_thread( TEB *teb ) DECLSPEC_HIDDEN;
 extern void signal_init_process(void) DECLSPEC_HIDDEN;
 extern void DECLSPEC_NORETURN signal_start_thread( PRTL_THREAD_START_ROUTINE entry, void *arg,
-                                                   BOOL suspend, void *relay, TEB *teb ) DECLSPEC_HIDDEN;
+                                                   BOOL suspend, void *relay, void *thunk, TEB *teb ) DECLSPEC_HIDDEN;
 extern void DECLSPEC_NORETURN signal_exit_thread( int status, void (*func)(int) ) DECLSPEC_HIDDEN;
 extern void __wine_syscall_dispatcher(void) DECLSPEC_HIDDEN;
 extern void fill_vm_counters( VM_COUNTERS_EX *pvmi, int unix_pid ) DECLSPEC_HIDDEN;
diff --git a/dlls/ntdll/unix/virtual.c b/dlls/ntdll/unix/virtual.c
index a2fea588834..fa46ec09668 100644
--- a/dlls/ntdll/unix/virtual.c
+++ b/dlls/ntdll/unix/virtual.c
@@ -2817,21 +2817,6 @@ done:
 }
 
 
-/***********************************************************************
- *           virtual_clear_thread_stack
- *
- * Clear the stack contents before calling the main entry point, some broken apps need that.
- */
-void virtual_clear_thread_stack( void *stack_end )
-{
-    void *stack = NtCurrentTeb()->Tib.StackLimit;
-    size_t size = (char *)stack_end - (char *)stack;
-
-    wine_anon_mmap( stack, size, PROT_READ | PROT_WRITE, MAP_FIXED );
-    if (force_exec_prot) mprotect( stack, size, PROT_READ | PROT_WRITE | PROT_EXEC );
-}
-
-
 /***********************************************************************
  *           virtual_map_user_shared_data
  */