The ROMs on these old boards typically don't have the driver needed to speak NVMe. Can't load your kernel if the UEFI doesn't know how to talk to your drive. This patch adds a driver to the ROM that allows it to natively access NVMe drives as block devices, solving the problem. Newer boards don't have this issue since nowadays it's standard practice to embed NvmExpressDxe or a similar driver from the factory.
Calwestjobs|9 months ago
or they ship with coreboot which can have final linux kernel payload without shims or kexec.