diff --git a/xCAT-server/lib/xcat/plugins/debian.pm b/xCAT-server/lib/xcat/plugins/debian.pm
index a54a8a3b5..fbae0f344 100644
--- a/xCAT-server/lib/xcat/plugins/debian.pm
+++ b/xCAT-server/lib/xcat/plugins/debian.pm
@@ -178,6 +178,43 @@ sub using_subiquity
     return 0;
 }
 
+# The first readable pair wins, so netboot trees precede live images and a
+# hardware-enablement kernel precedes the release one.
+my %INSTALL_BOOT_FILES = (
+    'x86' => [
+        [ 'install/hwe-netboot/ubuntu-installer/{darch}/linux', 'install/hwe-netboot/ubuntu-installer/{darch}/initrd.gz' ],
+        [ 'install/netboot/ubuntu-installer/{darch}/linux',     'install/netboot/ubuntu-installer/{darch}/initrd.gz' ],
+        [ 'install/netboot/vmlinuz',                            'install/netboot/initrd.gz' ],
+        [ 'casper/hwe-vmlinuz',                                 'casper/hwe-initrd' ],
+        [ 'casper/vmlinuz',                                     'casper/initrd' ],
+    ],
+    'ppc64' => [
+        [ 'install/netboot/ubuntu-installer/{darch}/vmlinux', 'install/netboot/ubuntu-installer/{darch}/initrd.gz' ],
+        [ 'install/vmlinux',                                  'install/netboot/initrd.gz' ],
+    ],
+);
+
+sub install_boot_files
+{
+    my ($arch, $darch, $pkgdir) = @_;
+    return unless defined($arch) && defined($pkgdir);
+    $darch = '' unless defined $darch;
+
+    my $family =
+        $arch =~ /x86/i   ? 'x86'
+      : $arch =~ /ppc64/i ? 'ppc64'
+      :                     undef;
+    return unless $family;
+
+    foreach my $candidate (@{ $INSTALL_BOOT_FILES{$family} }) {
+        my ($kernel, $initrd) = @{$candidate};
+        s/\{darch\}/$darch/g for ($kernel, $initrd);
+        ($kernel, $initrd) = ("$pkgdir/$kernel", "$pkgdir/$initrd");
+        return ($kernel, $initrd) if -r $kernel and -r $initrd;
+    }
+    return;
+}
+
 sub is_ubuntu_live_media
 {
     my $media_path = shift;
@@ -997,52 +1034,8 @@ sub mkinstall {
         my $initrdpath;
         my $maxmem;
 
-        if (
-            (
-                ($arch =~ /x86/ and
-                    (
-                        (-r "$pkgdir/install/hwe-netboot/ubuntu-installer/$darch/linux"
-                            and $kernpath = "$pkgdir/install/hwe-netboot/ubuntu-installer/$darch/linux"
-                            and -r "$pkgdir/install/hwe-netboot/ubuntu-installer/$darch/initrd.gz"
-                            and $initrdpath = "$pkgdir/install/hwe-netboot/ubuntu-installer/$darch/initrd.gz"
-                        ) or
-                        (-r "$pkgdir/install/netboot/ubuntu-installer/$darch/linux"
-                            and $kernpath = "$pkgdir/install/netboot/ubuntu-installer/$darch/linux"
-                            and -r "$pkgdir/install/netboot/ubuntu-installer/$darch/initrd.gz"
-                            and $initrdpath = "$pkgdir/install/netboot/ubuntu-installer/$darch/initrd.gz"
-                        ) or
-                        (-r "$pkgdir/install/netboot/vmlinuz"
-                            and $kernpath = "$pkgdir/install/netboot/vmlinuz"
-                            and -r "$pkgdir/install/netboot/initrd.gz"
-                            and $initrdpath = "$pkgdir/install/netboot/initrd.gz"
-                        ) or
-                        (-r "$pkgdir/casper/hwe-vmlinuz"
-                            and $kernpath = "$pkgdir/casper/hwe-vmlinuz"
-                            and -r "$pkgdir/casper/hwe-initrd"
-                            and $initrdpath = "$pkgdir/casper/hwe-initrd"
-                        ) or
-                        (-r "$pkgdir/casper/vmlinuz"
-                            and $kernpath = "$pkgdir/casper/vmlinuz"
-                            and -r "$pkgdir/casper/initrd"
-                            and $initrdpath = "$pkgdir/casper/initrd"
-                        )
-                    )
-                ) or (
-                    $arch =~ /ppc64/i and (
-                        (-r "$pkgdir/install/netboot/ubuntu-installer/$darch/vmlinux"
-                            and $kernpath = "$pkgdir/install/netboot/ubuntu-installer/$darch/vmlinux"
-                            and -r "$pkgdir/install/netboot/ubuntu-installer/$darch/initrd.gz"
-                            and $initrdpath = "$pkgdir/install/netboot/ubuntu-installer/$darch/initrd.gz"
-                        ) or
-                        (-r "$pkgdir/install/vmlinux"
-                            and $kernpath = "$pkgdir/install/vmlinux"
-                            and -r "$pkgdir/install/netboot/initrd.gz"
-                            and $initrdpath = "$pkgdir/install/netboot/initrd.gz"
-                        )
-                    )
-                )
-            )
-          ) {
+        ($kernpath, $initrdpath) = install_boot_files($arch, $darch, $pkgdir);
+        if ($kernpath) {
             #TODO: driver slipstream, targetted for network.
 
             # Copy the install resource to /tftpboot and check to only copy once
diff --git a/xCAT-test/unit/debian_install_boot_files.t b/xCAT-test/unit/debian_install_boot_files.t
new file mode 100644
index 000000000..b5783bc94
--- /dev/null
+++ b/xCAT-test/unit/debian_install_boot_files.t
@@ -0,0 +1,102 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use File::Path qw(make_path);
+use File::Temp qw(tempdir);
+use FindBin;
+use Test::More;
+
+# The installer kernel and initrd sit in a different place on every Ubuntu media layout:
+# netboot trees name them after the Debian architecture, live images keep them under
+# casper, and a hardware-enablement kernel ships beside the release one. Build each layout
+# on disk and ask the resolver, rather than reading the table that describes them.
+
+use lib "$FindBin::Bin/../../perl-xCAT";
+use lib "$FindBin::Bin/../../xCAT-server/lib/perl";
+my $plugin = "$FindBin::Bin/../../xCAT-server/lib/xcat/plugins/debian.pm";
+plan skip_all => 'debian.pm not found' unless -r $plugin;
+eval { require $plugin; 1 } or plan skip_all => "could not load debian.pm: $@";
+
+sub media {
+    my (@relative) = @_;
+    my $root = tempdir(CLEANUP => 1);
+    foreach my $path (@relative) {
+        my $full = "$root/$path";
+        ($full =~ m{^(.*)/[^/]+$}) and make_path($1);
+        open(my $fh, '>', $full) or die "cannot create $full: $!";
+        close($fh);
+    }
+    return $root;
+}
+
+sub resolved {
+    my ($arch, $darch, $root) = @_;
+    my ($kernel, $initrd) =
+      xCAT_plugin::debian::install_boot_files($arch, $darch, $root);
+    return unless defined $kernel;
+    s/^\Q$root\E\/// for ($kernel, $initrd);
+    return "$kernel|$initrd";
+}
+
+# --- x86_64 layouts, in the order the media are probed ---------------------
+is(
+    resolved('x86_64', 'amd64',
+        media('install/netboot/ubuntu-installer/amd64/linux',
+              'install/netboot/ubuntu-installer/amd64/initrd.gz')),
+    'install/netboot/ubuntu-installer/amd64/linux|install/netboot/ubuntu-installer/amd64/initrd.gz',
+    'a netboot tree is named after the Debian architecture',
+);
+is(
+    resolved('x86_64', 'amd64', media('casper/vmlinuz', 'casper/initrd')),
+    'casper/vmlinuz|casper/initrd',
+    'a live image keeps its kernel under casper',
+);
+is(
+    resolved('x86_64', 'amd64',
+        media('casper/hwe-vmlinuz', 'casper/hwe-initrd', 'casper/vmlinuz', 'casper/initrd')),
+    'casper/hwe-vmlinuz|casper/hwe-initrd',
+    'the hardware-enablement kernel wins over the release kernel',
+);
+is(
+    resolved('x86_64', 'amd64',
+        media('install/hwe-netboot/ubuntu-installer/amd64/linux',
+              'install/hwe-netboot/ubuntu-installer/amd64/initrd.gz',
+              'casper/vmlinuz', 'casper/initrd')),
+    'install/hwe-netboot/ubuntu-installer/amd64/linux|install/hwe-netboot/ubuntu-installer/amd64/initrd.gz',
+    'a netboot tree wins over a live image on the same media',
+);
+is(
+    resolved('x86_64', 'amd64', media('install/netboot/vmlinuz', 'install/netboot/initrd.gz')),
+    'install/netboot/vmlinuz|install/netboot/initrd.gz',
+    'the flat netboot layout resolves',
+);
+
+# --- ppc64 layouts ---------------------------------------------------------
+is(
+    resolved('ppc64', 'ppc64el',
+        media('install/netboot/ubuntu-installer/ppc64el/vmlinux',
+              'install/netboot/ubuntu-installer/ppc64el/initrd.gz')),
+    'install/netboot/ubuntu-installer/ppc64el/vmlinux|install/netboot/ubuntu-installer/ppc64el/initrd.gz',
+    'POWER keeps a vmlinux in its netboot tree',
+);
+is(
+    resolved('ppc64le', 'ppc64el', media('install/vmlinux', 'install/netboot/initrd.gz')),
+    'install/vmlinux|install/netboot/initrd.gz',
+    'the kernel and the initrd may sit in different directories',
+);
+is(
+    resolved('ppc64', 'ppc64el', media('casper/vmlinuz', 'casper/initrd')),
+    undef,
+    'POWER does not accept the x86 live layout',
+);
+
+# --- nothing to boot -------------------------------------------------------
+is(resolved('x86_64', 'amd64', media('casper/vmlinuz')), undef,
+    'a kernel without its initrd is not a match');
+is(resolved('x86_64', 'amd64', media('README')), undef,
+    'media with no installer resolves to nothing');
+is(resolved('s390x', 's390x', media('casper/vmlinuz', 'casper/initrd')), undef,
+    'an architecture the table does not describe resolves to nothing');
+
+done_testing();