A similar option is to boot a kernel using the built-in EFI stub (CONFIG_EFI_STUB=y), embed the initramfs if you use one (CONFIG_INITRAMFS_SOURCE), and set the default command line with CONFIG_CMDLINE if configuring it via UEFI is too unpleasant. I boot like this.

Advantage: less complex than adding another layer (and dependency) with the gummiboot stub.

Disadvantage: relinking the kernel is more expensive than rebundling with objcopy, if you change initramfs with the same kernel often.

Disadvantage: it's not an option if you use a distribution kernel binary instead of building your own.