Motherboard's latest BIOS doesn't support v-td, even though on a hardware level, it does. Reporting to GIGABYTE eSupport, they said: Mod needed: enabling vt-d. Latest bios from GIGABYTE's site, and a dump of the currently installed bios in a mediafire folder: /folder/ieql7e37bot4q/GA-P55-USB3L+(rev.+1.0) I'll add whatever info missing when asked or do whatever if this thread contains something wrong. Attached a dump because it may have more information for modders.
I never tried unlocking settings in Award. If I'm not mistaken, the setup utility of Award uses relative offsets table, which is simillar to AMI core 3 and Phoenix SCT. I will take a look. And If there is a hidden VT-d setting I might try unlocking. It would be good if there was an editor app to check if edits are correct. Know such? EDIT: It turned out VT-d was not simply unhidden. I checked USB3, USB3L, UD6 latest bios releases from support page. They don't have a mention of VT-d, while in the special USB3 bios by gigabyte it is present. Besides VT-d, gigabyte also added "1W Standby (S5)" mode setting and a warning message for DVID ocing.
It can be part of the source code, which gigabyte never made public, so rather "unwritten" than "hidden", Considering that the special USB3 bios was the result of direct request to their support team back when they still supported its motherboard. Anyway, looks grim.