201704 (20170502) ISO/usb images unbootable on ACPI v1 machines.
Even it is reported on IRC, and bug fix landed before making available 20170502 ISO/usb images,
images are published with osnet-incorporation/illumos that is unbootable die to already-fixed illumos loader bug.
20170502 ISO's/images should be recompiled to include bootable images.
(confirmed bootable pkg:/email@example.com) .
I suppose all ACPI v1 only machines are affected and images are useless for installation for the large chunk of fine and supported 64-bit hardware.