x370 mobo skips bios and boots to Win10 after 5.1

The purpose of this post is to document my experience with this product which includes the problems, my work-around solutions, and ongoing problems I do not have a solution for.

Problem: When the computer (motherboard) is powered on, it skips the GPU announcement screen, ASrock mobo logo, and the ability to press "del" to enter bios. After some time, windows 10 loads which function as normal. I believe the skipped screens are still happening, but behind a blank black screen.


Context: I'm trying to update my mobo's to a more recent bios so that it can receive zen 2 CPU (ryzen 9 3900x). Upgrading from Ryzen 5 1st generation.

Equipment:
Asrock X370 Killer SLI motherboard[URL=https://www.asrock.com/mb/AMD/X370%20Killer%20SLI/index.asp#BIOS]motherboard[/URL]
16gb ram
Ryzen 5 1500x
Geforce 1080 on primary pci slot
Geforce 1070 on 2ndary pci slot
Geforce 1070 on a PCI extender board
1000W gold PSU
*Machine stable and working daily for 2 years.

Process:
1. I followed the instructions found here to upgrade my mobo bios from 3.00 to 5.40 which I have successfully done.
[URL=https://www.asrock.com/mb/AMD/X370%20Killer%20SLI/index.asp#BIOS]here[/URL] The issue with "chipset driver" update is extremely confusing and I don't even know if I have done it correctly. I use Geforce GPU, why amd I installing Radeon software? I don't know of a way to verify that my chipset driver was installed correctly.
2. When successfully installing bios 5.10, the 'problem' described above occurs. This means I cannot go back into bios to flash to 5.40.
3. Had to scour the internet to identify that I need to take cmos battery out, do a cmos reset with the 3-pin jumper movement. bios post screen finally appeared on next power on, I entered bio, went under "advanced," and changed UFEI HD from "auto" to "off".
4. Reconnected all components of my PC together again to boot -> same 'problem' recurs.
5. Unplug 2 of my gpu and left the 1080 plugged in. The 'problem" is resolved after multiple restarts.
6. I flashed to 5.40 bios, which was my goal.

Conclusion:
After reaching my goal, the 'problem" still occurs when all 3 GPU are connected; but thankfully, I can always switch back to 1 gpu if I ever needed to access bios (annoying). I accepted living with the 'problem' and continue to use the PC to this writing.

I hope that Asrock can incorporate my experience into their product development and hopefully avoid such hassle to users in the future. Any suggestions on how I can resolve the problem with my current setup? BTW the problem was not an issue with Bios 3.00 and 3.50.

Issue is fully resolved as of now. Since installing the ryzen 9 3900x, I have also installed the bios version to 5.50. Did a clean GPU uninstall and reinstalled NVDIA's latest game driver. Everything is working like normal now, all 3 gpu is detected and usable by windows. I get the option to enter bios prior to Windows 10 loading.

Ray62, I always find these random forum comments when I come across my specific computer problems which where very helpful to me. I'm hoping to publicize my experience in case it may help another frustrated guy in the future.