diff --git a/dlls/kernel32/tests/comm.c b/dlls/kernel32/tests/comm.c
index 242b5993d1e..4e7fee52886 100644
--- a/dlls/kernel32/tests/comm.c
+++ b/dlls/kernel32/tests/comm.c
@@ -830,9 +830,7 @@ static void test_waittxempty(void)
 
     SetLastError(0xdeadbeef);
     res = WriteFile(hcom, tbuf, sizeof(tbuf), &bytes, NULL);
-todo_wine
     ok(!res, "WriteFile on an overlapped handle without ovl structure should fail\n");
-todo_wine
     ok(GetLastError() == ERROR_INVALID_PARAMETER, "expected ERROR_INVALID_PARAMETER, got %d\n", GetLastError());
 
     S(U(ovl_write)).Offset = 0;
@@ -2057,20 +2055,15 @@ static void test_read_write(void)
     bytes = 0xdeadbeef;
     SetLastError(0xdeadbeef);
     ret = WriteFile(hcom, atz, 0, &bytes, NULL);
-todo_wine
     ok(!ret, "WriteFile should fail\n");
-todo_wine
     ok(GetLastError() == ERROR_INVALID_PARAMETER, "expected ERROR_INVALID_PARAMETER, got %d\n", GetLastError());
     ok(bytes == 0, "bytes %u\n", bytes);
 
     iob.Status = -1;
     iob.Information = -1;
     status = pNtWriteFile(hcom, 0, NULL, NULL, &iob, atz, 0, NULL, NULL);
-todo_wine
     ok(status == STATUS_INVALID_PARAMETER, "expected STATUS_INVALID_PARAMETER, got %#x\n", status);
-todo_wine
     ok(iob.Status == -1, "expected -1, got %#x\n", iob.Status);
-todo_wine
     ok(iob.Information == -1, "expected -1, got %ld\n", iob.Information);
 
     for (i = -20; i < 20; i++)
@@ -2087,11 +2080,8 @@ todo_wine
         }
         else
         {
-todo_wine
             ok(status == STATUS_INVALID_PARAMETER, "%d: expected STATUS_INVALID_PARAMETER, got %#x\n", i, status);
-todo_wine
             ok(iob.Status == -1, "%d: expected -1, got %#x\n", i, iob.Status);
-todo_wine
             ok(iob.Information == -1, "%d: expected -1, got %ld\n", i, iob.Information);
         }
     }
diff --git a/dlls/ntdll/file.c b/dlls/ntdll/file.c
index 75ce35c4041..1cc8f8771b2 100644
--- a/dlls/ntdll/file.c
+++ b/dlls/ntdll/file.c
@@ -1016,6 +1016,15 @@ NTSTATUS WINAPI NtWriteFile(HANDLE hFile, HANDLE hEvent,
             goto done;
         }
     }
+    else if (type == FD_TYPE_SERIAL)
+    {
+        if (!(options & (FILE_SYNCHRONOUS_IO_ALERT | FILE_SYNCHRONOUS_IO_NONALERT)) &&
+            (!offset || (offset->QuadPart < 0 && offset->QuadPart != (LONGLONG)-1 /* FILE_WRITE_TO_END_OF_FILE */)))
+        {
+            status = STATUS_INVALID_PARAMETER;
+            goto done;
+        }
+    }
 
     for (;;)
     {