Without specifying IMAGE_FEATURES += "read-only-rootfs" the iso generated images will hang part way into the boot process. Tested on MinnowBoard core-image-sato ISO images with the new EFI/Hybrid work from Jason.
Moving to an All thing, as I suspect this isn't specific to the MinnowBoard and the MinnowBoard v1 bugs are getting closed right now.
There is no such issue in YP 1.8 any more.