Kudos to you @JRandomHacker , using your guide I was able to unlock a lot of hidden menus on my locked HP BIOS (AMI 7.12 Rev A, Motherboard Pegatron 2AB5 IPISB-CH2), and was able to make compatible and install a GTX 1060, in replacement of a previous GTX 760. The key is to switch the hidden setting "PCI ROM Priority" to Legacy ROM, and the card becomes compatible! (I suspect the UEFI oprom of the card doesn't like the UEFI part of my BIOS..) I dumped the flash using a CH341A programmer, to have a good backup with all my serials. I used this one with the tools. I followed everything, except that for my BIOS I needed to extract the body of the "freeform" section and NOT the compressed section, to give to IRFExtractor, otherwise it won't recognise the format. Otherwise, all went smooth, and I was able to put 010101010101 to unlock all the menus, to finally flash it back using my hardware programmer!
Thanks for your guide! I can confirm successfully unlocking the advanced menu on a Dell Inspiron 660 and also a Dell Inspiron 3847 (both AMI Aptio EFI BIOSes) using your method.
I was also able to use this guide to unlock the hidden menus on my HP Pavilion PC (HP Pavilion p6-2171a) with AMI Aptio EFI BIOS (AMI 8.20 dated Jan. 2015) for Motherboard Foxconn 2ADA Joshua H61. Edit: Patched SAFUWIN tool was needed to flash this BIOS. Posted here: https://forums.mydigitallife.net/th...ing-ami-aptio-ami-7-and-8.81742/#post-1597988