diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index 54c396fce6b..1232773e3ae 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -36,6 +36,8 @@ jobs:
             runner: [ ubuntu-24.04-ppc64le ]
           - env: { COMPILER: "gcc",   COMPILER_VERSION: "13", LINKER: "mold"  }
             runner: [ ubuntu-24.04-arm ]
+          - env: { COMPILER: "clang", COMPILER_VERSION: "18", LINKER: "lld"  }
+            runner: [ ubuntu-24.04-s390x ]
     env: ${{ matrix.env }}
     steps:
       - name: Repository checkout
diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index e92430274ea..4e4c9c964c1 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -29,11 +29,15 @@ jobs:
             runner: ubuntu-24.04-arm
           - run_phase: GCC
             runner: ubuntu-24.04-ppc64le
+          - run_phase: GCC
+            runner: ubuntu-24.04-s390x
           - run_phase: CLANG
           - run_phase: CLANG
             runner: ubuntu-24.04-arm
           - run_phase: CLANG
             runner: ubuntu-24.04-ppc64le
+          - run_phase: CLANG
+            runner: ubuntu-24.04-s390x
     steps:
       - name: Repository checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
diff --git a/src/test/test-tpm2.c b/src/test/test-tpm2.c
index 8277fab9782..4fd7afd4e2b 100644
--- a/src/test/test-tpm2.c
+++ b/src/test/test-tpm2.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "architecture.h"
 #include "hexdecoct.h"
 #include "tests.h"
 #include "tpm2-util.h"
@@ -875,6 +876,13 @@ static void check_tpm2b_public_from_rsa_pem(const char *pem, const char *hexn, u
 }
 
 TEST(tpm2b_public_from_openssl_pkey) {
+        // TODO: this test fails on s390x but only on Github Actions, re-enable once
+        // https://github.com/systemd/systemd/issues/38229 is fixed
+        if (strstr_ptr(ci_environment(), "github-actions") && uname_architecture() == ARCHITECTURE_S390X) {
+                log_notice("%s: skipping test on GH Actions because of systemd/systemd#38229", __func__);
+                return;
+        }
+
         /* standard ECC key */
         check_tpm2b_public_from_ecc_pem("2d2d2d2d2d424547494e205055424c4943204b45592d2d2d2d2d0a4d466b77457759484b6f5a497a6a3043415159494b6f5a497a6a30444151634451674145726a6e4575424c73496c3972687068777976584e50686a346a426e500a44586e794a304b395579724e6764365335413532542b6f5376746b436a365a726c34685847337741515558706f426c532b7448717452714c35513d3d0a2d2d2d2d2d454e44205055424c4943204b45592d2d2d2d2d0a",
                                         "ae39c4b812ec225f6b869870caf5cd3e18f88c19cf0d79f22742bd532acd81de",