Try disabling any "boot block" or bios protection settings in the bios; also any firewalls in windows defender or your virus software. I use the windows flash program, which most manufacturers offer now.
You need to download the newest version of @Bios off of Gigabyte's website to use the newest BIOS. Not the one that came on the disk with the board. And you have to use @Bios to flash, QFlsah will not work. At least for my UD4 that is true.