SONY VAIO SZ640 Ultra DMA

[aifel75]

I replaced the optical drive with 2nd hdd bay in a laptop SONY VAIO SZ640, it works but the drive only runs in Ultra DMA mode 2.
This is probably the limit set in the BIOS, because chipset ICH8 supports Ultra DMA Mode 6.
Can anyone help me unlock this restriction for the PATA primary port?

I use the unlocked Phoenix BIOS, version R0122S5 from the page: http://www.bios-mods.com/forum/Thread-So...2#pid42022