Well, As I said at the first post: I had no hope about this topic and GGTS confirm it. Looks like this was the last word:
"Dear Jose Gausachs ,
According to hard ware specification, the maxm speed is 92%. We have forward this issue to RD, your valuable feedback is the motivation for us to improve and serve you better. We will keep your suggestion in record to improve our service in the future. Again, sorry for the inconveinience that has encountered to your end.
Regards,
GIGABYTE TECHNOLOGY"
So, NO firmware, NO solution, nothing at all. Definitely this issue lets me think not to buy any other Gigabyte product but motherboards of course.