Comment 5 for bug 985258

This is not a bug in tasksel. Tasksel simply displays the tasks from the Packages files that it knows about. In the case of an x86 server install, it only knows about the packages that are present on the d-i-based CD. In the case of an armhf server preinstall image, it has pre-cached Packages files for all of the archive. So perhaps this is a bug in how we're choosing to build the images.