B450M Steel Legend, doesnt work after BIOS update

Hi all, yesterday I updated to the last bios version (3.90) my B450M Steel Legend, since I had my internal SSD (primary disk) often disconnected and Windows crashed. I had always to shut down the PC otherwise SSD was not detected by BIOS. Now my PC doesn't work anymore, showing black screen. LED and FAN is working but no screen is showed.
I already:
1) Clear CMOS using the pin
2) Removed the CMOS battery for all the night (14 hours), with power cable unplugged.
3) Removed SSD, graphic card, memory RAM (one at the time)
4) Tried power on with a USB pendrive with old BIOS file (renamed in CREATIVE.ROM)

Nothing works https://forum.asrock.com/smileys/smiley19.gif

I wrote an email to technical support but I haven't received any reply!!!

I will probably change the brand of my next mainboard. It's unacceptable that I haven't any support since I need an answer to understand if I've to throw away this motherboard to buy a new one or if I will be able to save it.

Someone has a suggestion?

My configuration is: ASROCK B450M Steel Legend, Palit GTX 1070ti JetStrem, RAM XPG spectrix d60 (8Gb X 2), SSD XPG SPECTRIX S40G RGB 512GB M.2 PCIe

Thanks

You're right   
I forgot to specify my CPU. It's a Ryzen 7 2700.

The reason for certain CPUs having their support dropped on older boards like B450 and X470 is due to physical ROM space, something has to give to make room for the newer CPU microcode. Asrock do also clearly state on the firmware download page not to use 3.90 if you have a Pinnacle, Summit, or Raven CPU but on the flipside of the coin I have mentioned for some time in Asrock reviews I've written (hi guys!) that they REALLY need to add a firmware flashback feature its been expected by enthusiasts for years now as it saves considerable inconvenience and time for the end user if a firmware update goes wrong while also having the benefit for Asrock of substantially cutting down on RMAs. Add to this that a firmware flashback feature is actually standard now on pretty much all other manufacturers boards and its more than high time Asrock also added this feature.

Many thanks. As I previuosly said I already lefted the PC more than 12 hours with CMOS battery removed and (of course) I tried before to discharge the mainboard using the power button pushed several times.
Now the PC is more than 24 hours without battery and this evening I will try with the tricks you told me.
I will let you know if I will be succeed.
In any case remove the support for old CPU for which a chipset has been deployed (B450M in this case) to support newer one is something absolutely wrong for my persepctive. If I want to move to a new CPU, I will be more inclined to purchase also a new motherboard with a new chipset (B550 for example).
BIOS update should be used mainly to fix issues and stability (in my case the problem I had with my SSD).

Many thanks again datonyb.

ket wrote: Manufacturers don't have a choice but to drop support for some CPUs on older boards in order to support new CPUs because the older boards don't have ROM chips large enough to store all of the data. Newer firmware revisions will typically focus on bugs and other issues related to newer CPUs so once updates start to come out that aren't focusing on your generation of CPU you know its time to stop updating the firmware anyway as there aren't going to be any improvements that will benefit you.

I'm not agree at all. B450 chipset was born for 1st and 2nd generation Ryzen. The motherboards manufacturers should improve stability and fix issue for that CPUs. If I want to move to a 3rd generation I will purchase a motherboard with B550 chipset (or X570) which are optimized for the new architecture and support new PCIe 4.0, USB 3.2, etc.

Intel from this point of view is more "professional" than AMD and their users have less problem than the AMD ones, for the Reason that AMD would have support for all the CPUS for all the Chipset but this is how to mend a dress for a boy everytime he is growing...