hi ive been using an HP Pavilion Gaming Laptop 15-dk1148TX for about 3 years.
undervolting was locked by the bios but i could still do it by changing some stuff using a modified grub. But after giving my laptop to a guy to replace my screen, for some reason he updated the bios and now i cant undervolt it. i cant change variables in grub and RU for some reason now. it shows cant write.
i tried downgrading but it shows cant verify signature or something.
Is there any way i could downgrade my bios to a previous version?
Any help would be much apreciated thanks. 
new bios files:
https://drive.google.com/file/d/1Dygid9OBr2g0sQUBEhBCEwTmEeP0VESy/view?usp=drive_link
old bios files:
https://drive.google.com/file/d/140BKVaML8hCnQ8HegZpK5KFA6QZqKyDl/view?usp=drive_link
The exe files:
https://drive.google.com/file/d/1cSkcrsVhK0jRFUVG0zzBsSQA6OoERBuJ/view?usp=drive_link