The good news: the BIOS update worked:
BIOS Version/Date American Megatrends International, LLC. MINISF003, 3/31/2025
SMBIOS Version 3.6
The bad news: the instructions that come with the BIOS download are woefully out of date. The update procedure is far different from what the instructions say, and I would have been in great trouble if I didn’t know how to use the Unix ls coommand. (Truth is I really don’t know and just guessed.) But I guessed correctly and everything completed OK.