Question MSI B450 Gaming: Mysterious BIOS issues

[Killerjockel]

Hi community
One month ago I built a new PC. It consists of the MSI B450 Gaming PLUS (mATX) Motherboard, the AMD Ryzen 5 3600, a Radeon RX 570 and runs on 16GB RAM. I knew I had to update the BIOS before using the system since the B450 mainboards don't have stock support of the Ryzen 3000 CPUs. So that's what I did using the "Flash BIOS button" and the system ran just fine for about a month. Than I ran into some Windows issues and decided to reinstall Windows 10. After yet some other issues I figured to run another clean installation, make sure all the drivers are fine and also check the BIOS.
I think I was on BIOS version 7B86v1A from 2019-07-23 once I initiated the update. This time I wanted to flash from the UEFI BIOS. It seems something went wrong. After more than 15 minutes nothing happened (I think the screen was black) so I decided to restart. The screen stayed black because it didn't get any input (that's what my monitor said).
Now I thought the BIOS was bricked and tried to restore the system by using the BIOS Flashback+ feature as when I first updated my BIOS. I downloaded the latest BIOS (7B86v1B from 2019-08-30) and ran used the button. The red LED flashed 3 times and stayed red thereafter. I called the support. They told me the stick was not being recognized and I will have to try another one. I tried 3 in total. All in FAT32, smallest one was 16 GB. I always had the BIOS renamed as "MSI.ROM" in the root of the stick. Always got the same result.
So I removed the BIOS battery and tried it again. Now I get a consistent red LED on the EZ Debug. It says CPU error which makes sense since the stock BIOS didn't support the CPU in the first place. But now when I try to run the BIOS update using the Flash BIOS button. The BIOS Flashback LED doesn't light up at all and only the EZ Debug LED complaints about the CPU. Should I run an earlier BIOS update first? Do I have to remove CPU, GPU, RAM or anything else before proceeding? Or is there anything else you think could be the issue here? I have no clue what's going on. Someone claimed the stick has to be MBR enabled. I tried that though. Maybe I did something wrong.
PLEASE HELP!

 

[stefanos50]

It happens to me everytime with B450 Tomahawk and Ryzen 5 3600. Everytime i want to flash a bios thought the BIOS then the screen goes black and nothing happens even if i restart. Now how you would fix that? You have to remove the CMOS battery for 5-10 mins to reset the bios. Then your pc will boot again without black screen. Then you go again to flash the new bios thought the BIOS and the second time you will be able to do it so. Also i believe when flashing from the bios its better to insert you usb drive not to the Msi flashback+ usb port but in any other. Hope it helps.

 

[Killerjockel]

Thanks stefanos! I have an update concerning the problem:

I found part of the solution. Seems like all of the time I tried to install the BIOS for the B450 instead of the B450M (the latter is the one I own...) jeez....
So now that I downloaded the proper BIOS the stick was recognized and so was the BIOS. The flash button worked and the newest BIOS should have been installed right? Btw. I tried the Clear CMOS pins and reinserted the BIOS battery while trying to fix the issue earlier.
But even though the newest BIOS should've been installed now I somehow still am unable to get a video signal on boot-up. Since the fans on the RX 570 were not spinning I tried using on board graphics and unplugged the GPU. Unfortunately I wasn't able to get a video signal from the mainboards HDMI port either. Maybe the fans were not spinning due to the lack of stress on the GPU?
So I'm back to the EZ Debug LED telling me there is something wrong with the CPU but I can't figure out what it is. Since the system was running okay prior to the BIOS issues I don't know what might be causing the issue. I think the latest BIOS should have been installed and so the mainboard should be able to work with the Ryzen 3000 CPU right? Any other ideas for troubleshooting?

EDIT: The EZ Debug LED change from CPU to DRAM once. I pushed the RAM in order to get all the pins to connect and then the board crashed? It went dark and either restarted automaticly or I had to do that I can't recall. But now it's back to showing the CPU LED-

 

[Killerjockel]

Update 2: So it seems that at first the system stopped operating because something went wrong with the BIOS flash. Maybe I also used the wrong BIOS back than and not only in the process of trying to fix it. And afterwards I was having issues booting because I hadn't inserted the RAM back properly after removing it for the CMOS reset. Everything is back at normal now. Thanks!