I made a freedos bootable USB disk with Rufus , then copied the bios.exe file to it, restarted my pc, opened the boot menu. I finally got to the freeDos ...
FreeDOS can be used to run DOS-based BIOS update utilities. A custom FreeDOS image which includes the necessary BIOS tools must be created. Gather firmware information · Boot-CD · FreeDOS environment
After flashing freeDOS to the drive, it's converted to iso9660, which is completely read-only. Per instructions, it just says to copy over the update file.