Had a similar issue with an ancient ASUS laptop - so old it didn’t even have wifi. Wouldn’t recognize the USB drive for booting. I had to flash the BIOS (got the file from the ASUS website), copy the BIOS file to an existing bootable partition on the hard drive (Debian, so /boot), flash it from the BIOS, enable UEFI and disable SecureBoot per the how-to - and then the USB drive with HA was visible for boot and worked fine.