No bootable device ~ oVirt 3.5 on Centos7

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In my initial attempt at getting oVirt 3.5 on Centos 7, I came across a pitfall when installing the hosted-engine.
Following the initial OS install of the hosted-engine via iso media, the first reboot encountered the ever present error “No boot device detected”, when selecting “Boot from local drive” or the like from the iso grub menu.
Unable to boot into the new OS, the engine-setup is halted.
The following list failed to fix the problem…

    reinstalling grub via rescue
    modifying the partition structure
    alternate installation media
    alternate OS in the hosted engine

The boot problem was only encountered when the host platform was Centos 7; Fed 20 & Centos 6.5 did not exhibit the problem.
The condensed version of my inquest is, that the “No bootable device” was peculiar to Centos 7, oVirt 3.5 and the ovirt-hosted-engine-setup vdsm generated instance.
The workaround is to edit the grub entry for “Boot from local drive” and change “.localboot 0xffff” to “.localboot 0x80”