This is the problem:

I have 2 arguments in winnt.sif in [GuiUnattended] , together doesn't work, anyone know how to separate arguments?

1 argument:

DetachedProgram=CMD.EXE
Arguments="/Q /C FOR /F %? IN ('%SYSTEMROOT%\SYSTEM32\MOUNTVOL.EXE^|FINDSTR :\') DO (IF EXIST %?\OEM\QuickLch\QuickLch.exe (START %?\OEM\QuickLch\QuickLch.exe && exit))"

2 argument:

DetachedProgram=".\system32\cmd.exe"
Arguments="/Q /C FOR /F %I IN (%SystemRoot%\SYSTEM32\$WINNT$.INF) DO (FOR %J IN (%I$OEM$) DO (IF EXIST %J (start /min /D%J NirCmd.exe exec hide Drivers.cmd)))";

And i try this:

DetachedProgram=".\system32\cmd.exe"
Arguments="/Q /C FOR /F %I IN (%SystemRoot%\SYSTEM32\$WINNT$.INF) DO (FOR %J IN (%I$OEM$) DO (IF EXIST %J (start /min /D%J NirCmd.exe exec hide Drivers.cmd)))"
"/Q /C FOR /F %? IN ('%SYSTEMROOT%\SYSTEM32\MOUNTVOL.EXE^|FINDSTR :\') DO (IF EXIST %?\OEM\QuickLch\QuickLch.exe (START %?\OEM\QuickLch\QuickLch.exe && exit))"

Sorry for me english but you sure understand

Having more than one command in DetachedProgram is not supported AFAIK.

Also what is this supposed to do?

FOR /F %I IN (%SystemRoot%\SYSTEM32\$WINNT$.INF) DO (FOR %J IN (%I$OEM$) DO (IF EXIST %J

In a general $WINNT$.INF that would produce lines like this:

FOR %J IN ([Unattend]$OEM$) DO (IF EXIST [Unattended]$OEM$

and

FOR %J IN (UnattendMode=FullUnattended$OEM$) DO IF EXIST UnattendMode...
IF EXIST FullUnattended$OEM$...

Wouldn't it be easier to just call a CMD file that contained all these commands?