That's great news!
I tried to update the BIOS with its EZ Flash 2 Utility, but when I provided the .rom file it said: "No upgrade information found on the file", something along those lines.
I found somewhere else that to circumvent that problem one had to install it from a DOS disk (!)
What do you think?
I've got it installed!
The trick was to put the .rom file in an USB drive, and pull it from there.
Unfortunately I still don't see any actual indication that this motherboard supports UEFI :(
For instance, after updating the BIOS I installed a booting GUI to replace the boring GRUB list-style booting, but it didn't work. GRUB is still there. This could suggest that UEFI is not available.
Also, the motherboard's page at Asus, while admittedly it won't say that it won't support UEFI, neither it says it does. Let alone even just mentioning the word UEFI.
...as this has been implemented for at least 5 years.
Right. Except this is not a recent motherboard. Its technology is older.
In fact, someone from an Asus (volunteer) forum confirm it not to have UEFI.
Oh well! Fortunately it's not a big deal. I just wanted to install a GUI for my booting files. At the moment I'm using GRUB, for both Windows and Linux.