refind-0.6.4 boots the kernel in a way that precludes an unsigned vmlinuz from being successfully booted if shim-signed is used to start refind itself and SecureBoot is not disabled; elilo-3.14 works just fine in the same environment. Reported upstream.
Worked around by booting ELILO instead (it's even not complete nonsense since refind is a boot manager and elilo is a boot loader ;-). http://git.altlinux.org/people/mike/packages/?p=mkimage.git;a=commitdiff;h=8a44277df8912acb7832192fb816692b2857fb18