Years ago I had an Acer ter-600. No matter what I did the boot time was 4 minutes. I tried everything I knew but it could not break the 4 minute mark. One day I got lucky and was running a disk scan on it and another machine. The disk scan speed was much faster on the other machine.

This gave me the idea that the speed limit was the hard disk. I changed the hard disk for the next step up in RPM and the boot time was then just under 2 minutes.

Many it's not a BIOS issue at all? Or your machine has little RAM. Hope this gives you ideas.
Bob