All hardware on the P67/Z68 boards are specific, based on AWARD BIOS (CPU and PWM controller,etc..).
So,to implement UEFI BIOS was been big ordeal.
Second limitation is BIOS chip size .
New Forum
as you said "BIOS Chip Size" but if look at board specification of two boards having z68 chipset but one is support and other is not support UEFI even after they both board have same size of BIOS chip.
GA-Z68X-UD3H-B3-rev 1.0 (According specification of Gigabyte website)
http://www.gigabyte.us/Motherboard/GA-Z68X-UD3H-B3-rev-10#spBIOS
2 x 32 Mbit flash
Use of licensed AWARD BIOS
Support for DualBIOS™
PnP 1.0a, DMI 2.0, SM BIOS 2.4, ACPI 1.0b
GA-Z68X-UD7-B3-rev 1.0
http://www.gigabyte.us/Motherboard/GA-Z68X-UD7-B3-rev-10#spBIOS
2 x 32 Mbit flash
Use of licensed AWARD BIOS
Support for DualBIOS™
PnP 1.0a, DMI 2.0, SM BIOS 2.4, ACPI 1.0b
may we know why this double standards with same size of bios and same chip set.
pardon (for words double standards)
Thanks
Parminder Singh
PS:- why i'm here because system need uefi bios according tech guy and i don't want to build new PC if my old PC can support my requirements but for i need 4TB of drive with UEFI(as per tech guy)