As of r294999 it’s possible to boot FreeBSD/amd64 stable/10 from ZFS pools on systems running UEFI firmware. Up until now I have booted my UEFI ZFS laptop using the older boot1.efi boot loader with /boot located on a UFS partition. Earlier today I updated my EFI System Partition (ESP), put /boot back where it belongs, in the ZFS pool, and scrapped the UFS partition. Thanks to everyone who made this happen.