diff --git a/tools/customize_ubuntu_image b/tools/customize_ubuntu_image
index 34b22fe..1ded664 100755
--- a/tools/customize_ubuntu_image
+++ b/tools/customize_ubuntu_image
@@ -69,8 +69,11 @@
     bind_dir "/sys" "${mount_dir}/sys"
     if [ -f /etc/apt/sources.list ]; then
       mirror=$(grep -oP 'https?://\K[^/ ]+' /etc/apt/sources.list|head -1)
-      if [ -f ${mount_dir}/etc/apt/sources.list ]; then
-          source ${mount_dir}/etc/os-release
+      if sudo test -f ${mount_dir}/etc/apt/sources.list.d/ubuntu.sources; then
+          sudo sed -Ei "s|(http[s]?://)([^/]+)|\1${mirror}|g" ${mount_dir}/etc/apt/sources.list.d/ubuntu.sources
+          sudo sed -i "/URIs:/a Trusted: yes" ${mount_dir}/etc/apt/sources.list.d/ubuntu.sources
+      elif sudo test -f ${mount_dir}/etc/apt/sources.list; then
+          source <(sudo cat ${mount_dir}/etc/os-release)
           sudo tee ${mount_dir}/etc/apt/sources.list <<EOF
           deb [ trusted=yes ] https://${mirror}/ubuntu ${UBUNTU_CODENAME} main universe
           deb [ trusted=yes ] https://${mirror}/ubuntu ${UBUNTU_CODENAME}-updates main universe