diff --git a/xCAT-genesis-builder/builddeb-genesis-base b/xCAT-genesis-builder/builddeb-genesis-base
index a6af7e9b1..e1c550ebd 100755
--- a/xCAT-genesis-builder/builddeb-genesis-base
+++ b/xCAT-genesis-builder/builddeb-genesis-base
@@ -80,7 +80,8 @@ REQUIRED_PACKAGES="
     nfs-common rpcbind pciutils usbutils parted
     dosfstools e2fsprogs lvm2 mdadm net-tools
     bc psmisc rsync wget cpio
-    isc-dhcp-client ifenslave util-linux-extra
+    isc-dhcp-client ifenslave
+    systemd-sysv hwdata btrfs-progs netcat-openbsd iputils-ping fdisk
     dpkg-dev debhelper fakeroot devscripts vim-tiny
 "
 if [ "$BUILDARCH" = "amd64" ]; then
@@ -89,6 +90,24 @@ fi
 
 echo "Installing build dependencies..."
 apt-get update -qq
+
+# Two commands the image needs changed package between releases: nslookup left dnsutils for
+# bind9-dnsutils in 22.04, and hwclock left util-linux for util-linux-extra in 23.04. Ask apt
+# which name this release carries rather than branch on the codename.
+add_first_available() {
+    local p
+    for p in "$@"; do
+        if apt-cache show "$p" >/dev/null 2>&1; then
+            REQUIRED_PACKAGES="$REQUIRED_PACKAGES $p"
+            return 0
+        fi
+    done
+    echo "ERROR: $CODENAME carries none of these packages: $*" >&2
+    exit 1
+}
+add_first_available bind9-dnsutils dnsutils
+add_first_available util-linux-extra util-linux
+
 apt-get install -y --no-install-recommends $REQUIRED_PACKAGES
 
 # dpkg-architecture comes from dpkg-dev, which the line above installs.
@@ -237,6 +256,9 @@ rewrite_control "$DIR/debian/control" "$BUILDARCH"
 # debian/dirs names the image directory, which is the rpm architecture.
 echo "/opt/xcat/share/xcat/netboot/genesis/$TARCH/" > "$DIR/debian/dirs"
 
+# dch reads debian/control from the current directory, not from the file it writes.
+cd "$DIR"
+
 PKG_VERSION="${VERSION}-${RELEASE}~${CODENAME}"
 rm -f "$DIR/debian/changelog"
 dch --create --package "xcat-genesis-base-$BUILDARCH" \
@@ -245,7 +267,6 @@ dch --create --package "xcat-genesis-base-$BUILDARCH" \
     "Native Ubuntu build on $CODENAME $BUILDARCH"
 
 echo "Building .deb package..."
-cd "$DIR"
 dpkg-buildpackage -rfakeroot -uc -us -b
 
 if [ -n "$outdir" ]; then
diff --git a/xCAT-test/unit/genesis_ubuntu_build_root.t b/xCAT-test/unit/genesis_ubuntu_build_root.t
index 1d87f7e63..4510cac3f 100755
--- a/xCAT-test/unit/genesis_ubuntu_build_root.t
+++ b/xCAT-test/unit/genesis_ubuntu_build_root.t
@@ -24,21 +24,25 @@ plan skip_all => 'ubuntu module-setup.sh not found' unless -f $module;
 plan tests => 9;
 
 # Commands the Ubuntu dracut module marks mandatory that a minimal Ubuntu server root does
-# NOT already provide, and the package that supplies each one. Every entry here has to be in
-# REQUIRED_PACKAGES or the image ships without the command.
-my %PACKAGE_FOR = (
-    dhclient  => 'isc-dhcp-client',
-    ifenslave => 'ifenslave',
-    hwclock   => 'util-linux-extra',
+# NOT already provide, and the packages that supply each one. Every command here needs one of
+# its packages in the build root or the image ships without it. hwclock has two names because
+# it left util-linux for util-linux-extra in 23.04, and the build root asks apt which name the
+# release it is building for carries.
+my %PACKAGES_FOR = (
+    dhclient  => ['isc-dhcp-client'],
+    ifenslave => ['ifenslave'],
+    hwclock   => [ 'util-linux-extra', 'util-linux' ],
 );
 
 my %mandatory = map { $_ => 1 } mandatory_commands($module);
 my @packages  = required_packages($builder);
 
-for my $command (sort keys %PACKAGE_FOR) {
+for my $command (sort keys %PACKAGES_FOR) {
+    my @provider = @{ $PACKAGES_FOR{$command} };
     ok($mandatory{$command}, "the Ubuntu dracut module installs '$command' unconditionally");
-    ok(scalar(grep { $_ eq $PACKAGE_FOR{$command} } @packages),
-       "the build root installs $PACKAGE_FOR{$command}, which provides '$command'");
+    my @named = grep { my $p = $_; grep { $_ eq $p } @packages } @provider;
+    ok(scalar @named,
+       "the build root installs @{[ join ' or ', @provider ]}, which provides '$command'");
 }
 
 # doxcat asks dhclient for the provisioning lease. An image without it never gets an address,
@@ -85,8 +89,10 @@ BASH
     return @names;
 }
 
-# required_packages($path): extract the REQUIRED_PACKAGES assignment from the build script and
-# evaluate it, so the list comes from the value the script actually uses.
+# required_packages($path): the packages the build root installs. The fixed list is the
+# REQUIRED_PACKAGES assignment, evaluated so the value comes from the script itself; a command
+# whose package name changed between releases is added by add_first_available, whose candidates
+# count too -- the script picks whichever one apt knows.
 sub required_packages {
     my ($path) = @_;
     my $text = do { open my $fh, '<', $path or die "$path: $!"; local $/; <$fh> };
@@ -95,5 +101,7 @@ sub required_packages {
     my $out = qx{bash -c 'set -u; $block; printf "%s\\n" \$REQUIRED_PACKAGES' 2>/dev/null};
     my @packages = grep { length } split /\s+/, ($out // '');
     BAIL_OUT("REQUIRED_PACKAGES in $path evaluated to nothing") unless @packages;
+    push @packages, grep { length } split /\s+/, $1
+        while $text =~ /^add_first_available\s+(.+)$/mg;
     return @packages;
 }