Cannot run on Intel NUC

[GToad]

Sorry for help.
I try to run boot/tinycore on my NUC with Intel i7-8559U. And I tried two ways.
First, I tried grub2 of Ubuntu 20.04 and take the ELF files below as the kernel:
NRE/nre/build/x86_64-release/bin/apps/hypervisor-elf64
NRE/nre/build/x86_64-release/bin/apps/hypervisor
NRE/kernel/nova/build/hypervisor-x86_64
However, I get the output: error: no multiboot header found from all the three ELF files above.

Then I tried the iso file generated from ./b bochs boot/tinycore. The path is NRE/nre/build/x86_64-release/tinycore.iso and I flush it to my USB flash disk. But my NUC output nothing.

I think I must have done something wrong. Please help me so I can run NRE on the real machine.