diff --git a/utils/packer/debian.json b/utils/packer/debian.json
index d2bd6c9..4addceb 100644
--- a/utils/packer/debian.json
+++ b/utils/packer/debian.json
@@ -32,10 +32,8 @@
       "type": "qemu",
       "vm_name": "qemu-{{ user `name` }}",
       "iso_checksum_type": "sha256",
-      "iso_checksum": "ad4e8c27c561ad8248d5ebc1d36eb172f884057bfeb2c22ead823f59fa8c3dff",
-      "iso_urls": [
-        "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/{{ user `iso_name` }}.iso"
-      ],
+      "iso_checksum_url": "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/SHA256SUMS",
+      "iso_url": "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/{{ user `iso_name` }}.iso",
       "shutdown_command": "echo '{{ user `ssh_password` }}' | sudo -S shutdown -P now",
       "disk_size": "{{ user `disk_size` }}",
       "headless": "{{ user `headless` }}",
@@ -74,10 +72,8 @@
       "type": "virtualbox-iso",
       "vm_name": "virtualbox-{{ user `name` }}",
       "iso_checksum_type": "sha256",
-      "iso_checksum": "ad4e8c27c561ad8248d5ebc1d36eb172f884057bfeb2c22ead823f59fa8c3dff",
-      "iso_urls": [
-        "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/{{ user `iso_name` }}.iso"
-      ],
+      "iso_checksum_url": "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/SHA256SUMS",
+      "iso_url": "{{ user `debian_mirror` }}/{{ user `debian_version` }}/amd64/iso-cd/{{ user `iso_name` }}.iso",
       "shutdown_command": "echo 'vagrant' | sudo -S shutdown -P now",
       "disk_size": "{{ user `disk_size` }}",
       "headless": "{{ user `headless` }}",
diff --git a/utils/packer/http/ubuntu-16.04/preseed.cfg b/utils/packer/http/ubuntu-16.04/preseed.cfg
index d375c22..237b3a0 100644
--- a/utils/packer/http/ubuntu-16.04/preseed.cfg
+++ b/utils/packer/http/ubuntu-16.04/preseed.cfg
@@ -3,7 +3,7 @@ d-i debian-installer/language string en
 d-i debian-installer/country string US
 d-i debian-installer/locale string en_US.UTF-8
 d-i keyboard-configuration/xkb-keymap select us
-d-i base-installer/kernel/override-image string linux-server
+d-i base-installer/kernel/override-image string linux-generic-hwe-16.04
 d-i clock-setup/utc-auto boolean true
 d-i clock-setup/utc boolean true
 d-i debconf/frontend select noninteractive
diff --git a/utils/packer/ubuntu.json b/utils/packer/ubuntu.json
index 5a78447..f593b17 100644
--- a/utils/packer/ubuntu.json
+++ b/utils/packer/ubuntu.json
@@ -30,7 +30,7 @@
       "type": "qemu",
       "vm_name": "qemu-{{ user `name` }}",
       "iso_checksum_type": "sha256",
-      "iso_checksum": "29a8b9009509b39d542ecb229787cdf48f05e739a932289de9e9858d7c487c80",
+      "iso_checksum_url": "{{ user `ubuntu_mirror` }}{{ user `ubuntu_version` }}/SHA256SUMS",
       "iso_url": "{{ user `ubuntu_mirror` }}{{ user `ubuntu_version` }}/{{ user `iso_name` }}.iso",
       "shutdown_command": "echo '{{ user `ssh_password` }}' | sudo -S shutdown -P now",
       "disk_size": "{{ user `disk_size` }}",
@@ -76,7 +76,7 @@
       "type": "virtualbox-iso",
       "vm_name": "virtualbox-{{ user `name` }}",
       "iso_checksum_type": "sha256",
-      "iso_checksum": "29a8b9009509b39d542ecb229787cdf48f05e739a932289de9e9858d7c487c80",
+      "iso_checksum_url": "{{ user `ubuntu_mirror` }}{{ user `ubuntu_version` }}/SHA256SUMS",
       "iso_url": "{{ user `ubuntu_mirror` }}{{ user `ubuntu_version` }}/{{ user `iso_name` }}.iso",
       "shutdown_command": "echo '{{ user `ssh_password` }}' | sudo -S shutdown -P now",
       "disk_size": "{{ user `disk_size` }}",