Thanks, Serg008. Bios is working perfectly with Win7 Ultimate 64 using included ASUS cert. A quick note about a minor issue, however. Your zip file includes BUPDATER.EXE V1.12. I tried to back up my old Bios before flashing but couldn't, always getting an error message about the utility not being able to read current flash contents. Switched to V1.00b, available from ASUS support site when you look for Bios utilities for P7P55D-LE. That version was able to backup my old Bios and reflash with yours.
Modified Gigabyte 2.1 Bios link: Gigabyte_GA-X58A-UD3R_(Rev_2.x)_FE_Gigabyte_SLIC_2.1_SSV3.rar Confirmed - works great and my computer remains intact. Thanks for the effort mate.