Yeah, this was my one concern with the setup. But to be fair, it's not a flaw with efistub, it's a flaw with the kernel update logic in arch. I manually added an entry for a known good configuration which I periodically updated manually, but I know of no reason why the kernel update logic couldn't do that for me like it does in grub. And as a fallback you can install a UEFI shell option to boot into which works in emergencies.