mitchellh/packer — pull request #1453 by manul (2014-08-29 07:29:17+00:00)
Title: It's possible to create instance-store images from EBS-based images

It's not necessary to use an instance-store image to build an instance-store image, see this example http://sorcery.smugmug.com/2014/01/29/instance-store-hvm-amis-for-amazon-ec2/ so there should be no restriction on the ExpectedRootDevice