Package: debian-installer
Version: 20160516+b1
Installing Debian using QEMU aarch64 (and looks like arm as well) requires extra steps due to lack of initrd and kernel support for virtio devices. While there is a workaround documented below, this seems like something that should be added to the distro build to incorporate support directly.
https://gmplib.org/~tege/qemu.htmlSee block 14.