How large a USB stick do I need? I've got some ancient 64MB ones that I'd like to use for this, if possible. I've tried using diskutil partitionDisk /dev/disk3 MBR MS-DOS X10SL7F 0b at the CLI in macOS, but Disk Utility says the resulting USB stick is not bootable.
How would I create a bootable USB stick using macOS 10.13? All the info I've found so far assumes you want to use an ISO to make a bootable USB stick, so they point to tools like UNetbootin. Do I need to add an OS such as FreeDOS, or are the contents of the BIOS zip from Supermicro all I need? I've downloaded the 3.0a BIOS for each of these boards, and if I understand the directions correctly, I 'simply' need to copy the contents of the expanded zip files onto a bootable USB stick. I want to update the BIOS on my two servers with Supermicro boards (X10SRH-cF and X10SL7-F).