I'm assuming the issue is that some exploit in the last year has resulted in the UEFI being revoked. Can I ignore this warning, turn off secure boot, update Ubuntu, and then turn it back on? Or do I ...

I'm trying to apply an individual BIOS update to many servers. In the old days, I'd use Rufus to make a USB stick bootable, copy the BIOS update file to it, walk to the server room, plug it in, boot ...