A bootable USB DOS drive (use Rufus to create one with FreeDOS).
and wait for the system to restart. The update will continue during the reboot.
Intel officially removed legacy product download pages in 2021. Here are safe, verified sources (always scan with antivirus):
Intel typically offers multiple ways to update these boards, though official support has moved to archival status: Intel® Desktop Board DH61BF
Open Command Prompt as administrator and type: