Diskpart and Sata HDD

Hello,

From BartPe i execute a cmd file, who create a c:\ partition of 30gb via Diskpart.

It works well with an ide HDD.

But i have tested with a SATA HDD, and diskpart seems not to want my limitation of 30GB.

Here my diskpart.cmd:

%windir%\system32\net start dmadmin

diskpart.exe /s diskpart.txt

echo o | FORMAT C: /fs:ntfs /q

Here my diskpart.txt

select disk 0

clean

create partition primary size=30000

assign letter c

active

exit

Do you know why Diskpart takes the whole space on the HDD?

Thks a lot