Hi there.
I had the same problem. Bios seemed to update, but when rebooting and entering the BIOS, I had de same version.
As they say, use Instant Flash. That did it for me. Just put the BIOS version you want on a USB, then restart computer, enter ASrock BIOS and select "instant flash". The motherboard will find the compatible BIOS versions on the USB for you. Select the one you want to install and that´s it. Ready to go.