Trying to install Linux on an old (~10 years) computer, the UEFI flash install wouldn't "take".
For these situations, the traditional dd method still seems to work best. I followed these instructions, as the accepted answer for that question didn't work either. Not sure whether the isohybrid and syslinux section was needed, or if just the simple dd command (as per this answer would have been enough.
The core difference between the UEFI setup linked above seems to be using the whole flash drive (eg /dev/sdd) rather than a specific partition (eg /dev/sdd1) when unpacking the ISO.
The essential command may simply be this:
dd if='/path/to/file.iso' of=/dev/sdX bs=8M