Всем спасибо. Решил проблему вот таким бат-файлом, который запускаю из winnt.sif:
Код:

[SetupParams]
UserExecute = "%windir%\system32\BootScreen\BootScreen.cmd"
BootScreen.cmd:
Код:

cmdow @ /HID
@echo off
Title Копирование пропатченного Boot Screen-на
ECHO.
REM===========================
ECHO Резервоное копирование оригинальных файлов
XCOPY "%Windir%\$hf_mig$\KB931784\SP2QFE\*.*" "%Windir%\system32\BootScreen\Original\" /c /h /q /y
REM====================================
ECHO.
ECHO Заменяем оригинальные файлы на пропатченные
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlmp.exe" "%Windir%\system32\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlmp.exe" "%Windir%\system32\dllcache\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlmp.exe" "%Windir%\Driver Cache\i386\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlmp.exe" "%Windir%\$hf_mig$\KB931784\SP2QFE\" /c /h /q /y
ECHO.
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlpa.exe" "%Windir%\system32\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlpa.exe" "%Windir%\system32\dllcache\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlpa.exe" "%Windir%\Driver Cache\i386\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrnlpa.exe" "%Windir%\$hf_mig$\KB931784\SP2QFE\" /c /h /q /y
ECHO.
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrpamp.exe" "%Windir%\system32\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrpamp.exe" "%Windir%\system32\dllcache\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrpamp.exe" "%Windir%\Driver Cache\i386\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntkrpamp.exe" "%Windir%\$hf_mig$\KB931784\SP2QFE\" /c /h /q /y
ECHO.
XCOPY "%Windir%\system32\BootScreen\Patch\ntoskrnl.exe" "%Windir%\system32\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntoskrnl.exe" "%Windir%\system32\dllcache\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntoskrnl.exe" "%Windir%\Driver Cache\i386\" /c /h /q /y
XCOPY "%Windir%\system32\BootScreen\Patch\ntoskrnl.exe" "%Windir%\$hf_mig$\KB931784\SP2QFE\" /c /h /q /y
EXIT