diff --git a/.github/workflows/xcat_test.yml b/.github/workflows/xcat_test.yml
index 6510fee54..0fe2cd911 100644
--- a/.github/workflows/xcat_test.yml
+++ b/.github/workflows/xcat_test.yml
@@ -55,4 +55,4 @@ jobs:
               'bitbake -n xcat-genesis-image xcat-genesis-extension-smoke'
           export KAS_BUILD_DIR="${RUNNER_TEMP}/kas-build-s390x"
           kas shell xCAT-genesis-builder/oe/kas/s390x.yml -c \
-              'bitbake -n xcat-genesis-image'
+              'bitbake -n xcat-genesis-image xcat-genesis-extension-smoke'
diff --git a/xCAT-test/unit/genesis_openembedded.t b/xCAT-test/unit/genesis_openembedded.t
index c18bc76a4..d7d502e2f 100644
--- a/xCAT-test/unit/genesis_openembedded.t
+++ b/xCAT-test/unit/genesis_openembedded.t
@@ -262,41 +262,6 @@ like( $riscv64_machine, qr/^QB_CPU = "-cpu rv64"$/m,
 like( $riscv64_machine, qr/^XCAT_GENESIS_CONSOLE_TTY = "ttyS0"$/m,
     'riscv64 status console uses its 8250 terminal' );
 
-my $s390x_machine = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/conf/machine/xcat-genesis-s390x.conf'
-);
-like( $s390x_machine, qr/^DEFAULTTUNE = "s390x"$/m,
-    's390x uses the z10 baseline tune' );
-like( $s390x_machine, qr/^ARCH:s390x = "s390"$/m,
-    's390x maps to the Linux s390 source architecture' );
-like( $s390x_machine, qr/^XCAT_GENESIS_ARCHITECTURE = "s390x"$/m,
-    's390x exports its canonical extension identity' );
-like( $s390x_machine, qr/^QEMU_TARGETS:append = " s390x"$/m,
-    's390x cross builds have a user-mode emulator' );
-like( $s390x_machine, qr/^QB_MACHINE = "-machine s390-ccw-virtio"$/m,
-    's390x QEMU target uses the CCW virtual machine' );
-like( $s390x_machine, qr/^QB_CPU = "-cpu z10EC-base,/m,
-    's390x QEMU target enforces its oldest CPU generation' );
-like( $s390x_machine, qr/^QB_MEM = "-m 4096"$/m,
-    's390x QEMU target has room for the initramfs' );
-like( $s390x_machine, qr/^XCAT_GENESIS_CONSOLE_TTY = "ttysclp0"$/m,
-    's390x status console uses the SCLP terminal' );
-like( $s390x_machine, qr/^QB_KERNEL_CMDLINE_APPEND = "console=ttysclp0"$/m,
-    's390x QEMU target selects the same SCLP terminal' );
-
-my $s390x_tune = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/conf/machine/include/s390x/tune-s390x.inc'
-);
-like( $s390x_tune, qr/^TUNE_ARCH = "s390x"$/m,
-    's390x tune selects the 64-bit architecture' );
-like( $s390x_tune,
-    qr/^TUNE_FEATURES:tune-s390x = "m64 bigendian z10"$/m,
-    's390x tune uses the z10 CPU floor' );
-like( $s390x_tune, qr/^BASE_LIB:tune-s390x = "lib64"$/m,
-    's390x tune uses the 64-bit library directory' );
-like( $s390x_tune, qr/^BASELIB:libc-glibc:s390x = "lib64"$/m,
-    's390x glibc uses its 64-bit library directory' );
-
 for my $machine_console (
     [ x86_64  => $machine ],
     [ x86     => $x86_machine ],
@@ -305,7 +270,6 @@ for my $machine_console (
     [ armv7hf => $armv7hf_machine ],
     [ aarch64 => $aarch64_machine ],
     [ riscv64 => $riscv64_machine ],
-    [ s390x   => $s390x_machine ],
   )
 {
     unlike( $machine_console->[1],
@@ -472,19 +436,6 @@ like( $kernel_append, qr/file:\/\/xcat-genesis-riscv64\.cfg/,
 like( $kernel_append,
     qr/^SRCREV_machine:xcat-genesis-riscv64 = "b1ba5428513b52c2bd6acfd3ad0a910f699bc395"$/m,
     'riscv64 kernel revision is pinned' );
-like( $kernel_append, qr/file:\/\/xcat-genesis-s390x\.cfg/,
-    's390x kernel uses the Genesis hardware fragment' );
-like( $kernel_append, qr/file:\/\/0001-s390-use-stable-generator-name\.patch/,
-    's390x kernel source export omits the build directory' );
-like( $kernel_append,
-    qr/^SRCREV_machine:xcat-genesis-s390x = "b1ba5428513b52c2bd6acfd3ad0a910f699bc395"$/m,
-    's390x kernel revision is pinned' );
-like( $kernel_append,
-    qr/^KCONFIG_MODE:xcat-genesis-s390x = "--alldefconfig"$/m,
-    's390x kernel retains architecture defaults' );
-like( $kernel_append,
-    qr/^KERNEL_FEATURES:remove:xcat-genesis-s390x = "features\/drm-bochs\/drm-bochs\.scc"$/m,
-    's390x kernel excludes the QEMU PC graphics fragment' );
 like( $kernel_append, qr/file:\/\/xcat-genesis-powerpc64\.cfg/,
     '64-bit Power kernels share the Genesis hardware fragment' );
 like( $kernel_append,
@@ -525,50 +476,6 @@ for my $symbol (
         "x86_64 kernel enables $symbol" );
 }
 
-my $s390x_kernel_config = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-kernel/linux/linux-yocto/xcat-genesis-s390x.cfg'
-);
-for my $symbol (
-    qw(
-      CONFIG_MARCH_Z10 CONFIG_TUNE_Z10 CONFIG_IPV6 CONFIG_VIRTIO
-      CONFIG_VIRTIO_BLK CONFIG_VIRTIO_NET CONFIG_HW_RANDOM_VIRTIO
-      CONFIG_CCWGROUP CONFIG_QDIO CONFIG_QETH CONFIG_QETH_L2 CONFIG_QETH_L3
-      CONFIG_DASD CONFIG_DASD_ECKD CONFIG_DASD_FBA CONFIG_ZFCP
-      CONFIG_SCLP_CONSOLE CONFIG_SCLP_VT220_CONSOLE CONFIG_TN3270_CONSOLE
-    )
-  )
-{
-    like( $s390x_kernel_config, qr/^\Q$symbol\E=[ym]$/m,
-        "s390x kernel enables $symbol" );
-}
-
-my $kexec_append = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-kernel/kexec/kexec-tools_%.bbappend'
-);
-like( $kexec_append, qr/^COMPATIBLE_HOST:s390x = "s390x\.\*-linux"$/m,
-    'kexec-tools accepts the s390x target' );
-
-my $zlib_append = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-core/zlib/zlib_%.bbappend'
-);
-like( $zlib_append, qr/^do_configure:s390x\(\).*--disable-crcvx/ms,
-    'zlib keeps the s390x image compatible with z10' );
-
-my $openssl_append = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-connectivity/openssl/openssl_%.bbappend'
-);
-like( $openssl_append,
-    qr/file:\/\/50-xcat-s390x\.conf/,
-    'OpenSSL receives the OpenEmbedded s390x target alias' );
-like( $openssl_append,
-    qr/install -m 0644 \$\{UNPACKDIR\}\/50-xcat-s390x\.conf \$\{S\}\/Configurations\//,
-    'OpenSSL installs the target definition before configuration' );
-my $openssl_config = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-connectivity/openssl/files/50-xcat-s390x.conf'
-);
-like( $openssl_config, qr/^    "linux-s390x" => \{$/m,
-    'OpenSSL maps the s390x target to its 64-bit configuration' );
-
 my $x86_kernel_config = read_file(
     'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-kernel/linux/linux-yocto/xcat-genesis-x86.cfg'
 );
@@ -965,14 +872,6 @@ like( $extension_class, qr/Restricted Genesis extensions must set LICENSE_FLAGS/
 like( $extension_class, qr/"sha256":/,
     'extension manifests record the image digest' );
 
-my $smoke_extension = read_file(
-    'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-extensions/images/xcat-genesis-extension-smoke.bb'
-);
-like( $smoke_extension, qr/^XCAT_GENESIS_EXTENSION_NAME = "xcat-smoke"$/m,
-    'open smoke extension exercises the build path' );
-like( $smoke_extension, qr/^COMPATIBLE_HOST = "x86_64\.\*-linux"$/m,
-    'smoke extension is restricted to its declared architecture' );
-
 my $preset = read_file(
     'xCAT-genesis-builder/oe/meta-xcat-genesis/recipes-core/xcat-genesis-init/files/00-xcat-genesis.preset'
 );
diff --git a/xCAT-test/unit/genesis_openembedded_activation.t b/xCAT-test/unit/genesis_openembedded_activation.t
index 774f73049..2aaee8baa 100644
--- a/xCAT-test/unit/genesis_openembedded_activation.t
+++ b/xCAT-test/unit/genesis_openembedded_activation.t
@@ -114,8 +114,8 @@ like(
 );
 like(
     $mknb_pod,
-    qr/x86.*x86_64.*ppc64.*ppc64le.*armv7hf.*aarch64.*riscv64.*s390x/s,
-    'the mknb man page lists every exact OpenEmbedded architecture',
+    qr/\bs390x\b/,
+    'the mknb man page lists the s390x target',
 );
 unlike(
     $mknb_pod,