BIOS recovery after unsuccessful firmware, please

??Greetings, the ASROCK Z390M-itx motherboard was purchased, Intel Core i3-8100, DIMM DDR4, 8GB, Kingston HyperX Predator, 240GB SSD, M.2, PCIe 3.0, Kingston A1000.

After the build, I decided to go into the UEFI BIOS and check for updates, after searching it was suggested to upgrade to the latest BIOS version from 2019/6/11 (before the update was from 2019/3/28), then the update was loaded in a few minutes, the computer went to reboot, ran a line of 2-3 words on the monitor for a split second, did not have time to read, and the PC just turned off, I waited a few minutes thinking that the process was on, but nothing happened. I decided to turn it on, and everything, black screen, the board does not start. There were attempts to reset the BIOS through the jumper, removing the battery, also slipped the USB flash drive with BIOS from March 28, without result (disconnecting the entire keyboard except the keyboard on the PC / 2). I also connected a discrete video card with an analog output, also a zero effect. Help please, maybe someone came across a similar! I apologize for my english, this is all google translate.

Xaltar wrote: Follow the steps here to fully clear CMOS and reset the RTC: http://forum.asrock.com/forum_posts.asp?TID=630&title=how-to-clear-cmos-via-battery-removal If that does not work you will have to contact ASRock Tech Support here: https://event.asrock.com/tsd.asp

Thanks for the answer, I will try, I will answer you.

This motherboard does not have USB flashback unfortunately so your only option is to get system to boot in current state.

One thing what you could try is to remove cmos battery completely and leave system for couple of hours to ensure all capacitors have every power drained.

Then try to start system (POST) with minimal config: atx + cpu power connected to motherboard, processor, memory and one graphics cable. No need to even connect usb (keyboard/mouse).

If this doesn't help you have to return the board for service :(