diff --git a/test/TEST-21-DFUZZER/test.sh b/test/TEST-21-DFUZZER/test.sh
index 42e37c8a9c..7669e4e0ad 100755
--- a/test/TEST-21-DFUZZER/test.sh
+++ b/test/TEST-21-DFUZZER/test.sh
@@ -6,6 +6,8 @@ TEST_DESCRIPTION="Fuzz our D-Bus interfaces with dfuzzer"
 TEST_NO_NSPAWN=1
 TEST_SUPPORTING_SERVICES_SHOULD_BE_MASKED=0
 QEMU_TIMEOUT="${QEMU_TIMEOUT:-1800}"
+IMAGE_NAME=dfuzzer
+TEST_FORCE_NEWIMAGE=1
 
 # shellcheck source=test/test-functions
 . "${TEST_BASE_DIR:?}/test-functions"
diff --git a/test/TEST-36-NUMAPOLICY/test.sh b/test/TEST-36-NUMAPOLICY/test.sh
index 5f38bf1009..7909b1dce3 100755
--- a/test/TEST-36-NUMAPOLICY/test.sh
+++ b/test/TEST-36-NUMAPOLICY/test.sh
@@ -9,7 +9,7 @@ TEST_NO_NSPAWN=1
 . "${TEST_BASE_DIR:?}/test-functions"
 
 if qemu_min_version "5.2.0"; then
-    QEMU_OPTIONS="-object memory-backend-ram,id=mem0,size=${QEMU_MEM:?} -numa node,memdev=mem0,nodeid=0"
+    QEMU_OPTIONS="-object memory-backend-ram,id=mem0,size=${QEMU_MEM:-512M} -numa node,memdev=mem0,nodeid=0"
 else
     QEMU_OPTIONS="-numa node,nodeid=0"
 fi
diff --git a/test/test-functions b/test/test-functions
index f4dd673522..bc479b3e79 100644
--- a/test/test-functions
+++ b/test/test-functions
@@ -30,7 +30,6 @@ TIMED_OUT=  # will be 1 after run_* if *_TIMEOUT is set and test timed out
 [[ "$LOOKS_LIKE_SUSE" ]] && FSTYPE="${FSTYPE:-btrfs}" || FSTYPE="${FSTYPE:-ext4}"
 UNIFIED_CGROUP_HIERARCHY="${UNIFIED_CGROUP_HIERARCHY:-default}"
 EFI_MOUNT="${EFI_MOUNT:-$(bootctl -x 2>/dev/null || echo /boot)}"
-QEMU_MEM="${QEMU_MEM:-512M}"
 # Note that defining a different IMAGE_NAME in a test setup script will only result
 # in default.img being copied and renamed. It can then be extended by defining
 # a test_append_files() function. The $1 parameter will be the root directory.
@@ -262,7 +261,7 @@ if get_bool "$IS_BUILT_WITH_ASAN"; then
     STRIP_BINARIES=no
     SKIP_INITRD="${SKIP_INITRD:-yes}"
     PATH_TO_INIT=$ROOTLIBDIR/systemd-under-asan
-    QEMU_MEM="2048M"
+    QEMU_MEM="${QEMU_MEM:-2G}"
     QEMU_SMP="${QEMU_SMP:-4}"
 
     # We need to correctly distinguish between gcc's and clang's ASan DSOs.
@@ -456,7 +455,7 @@ run_qemu() {
     qemu_options+=(
         -smp "$QEMU_SMP"
         -net none
-        -m "$QEMU_MEM"
+        -m "${QEMU_MEM:-512M}"
         -nographic
         -kernel "$KERNEL_BIN"
         -drive "format=raw,cache=unsafe,file=$image"
diff --git a/test/units/testsuite-21.sh b/test/units/testsuite-21.sh
index 43b5fb6f22..e9bf18603a 100755
--- a/test/units/testsuite-21.sh
+++ b/test/units/testsuite-21.sh
@@ -8,22 +8,16 @@ set -o pipefail
 systemctl list-jobs | grep -F 'end.service' && SHUTDOWN_AT_EXIT=1 || SHUTDOWN_AT_EXIT=0
 
 at_exit() {
-    # "Safety net" - check for any coredumps which might have not caused dfuzzer
-    # to stop & return an error (we need to do this now before truncating the
-    # journal)
-    # TODO: check fo ASan/UBSan errors
-    local found_cd=0
-    while read -r exe; do
-        coredumctl info "$exe"
-        found_cd=1
-    done < <(coredumpctl -F COREDUMP_EXE | sort -u)
-    [[ $found_cd -eq 0 ]] || exit 1
-
-    # We have to call the end.service explicitly even if it's specified on
+    set +e
+    # We have to call the end.service/poweroff explicitly even if it's specified on
     # the kernel cmdline via systemd.wants=end.service, since dfuzzer calls
     # org.freedesktop.systemd1.Manager.ClearJobs() which drops the service
     # from the queue
-    [[ $SHUTDOWN_AT_EXIT -ne 0 ]] && systemctl start --job-mode=flush end.service
+    if [[ $SHUTDOWN_AT_EXIT -ne 0 ]] && ! systemctl poweroff; then
+        # PID1 is down let's try to save the journal
+        journalctl --sync || : # journal can be down as well so let's ignore exit codes here
+        systemctl -ff poweroff # sync() and reboot(RB_POWER_OFF)
+    fi
 }
 
 trap at_exit EXIT
@@ -72,7 +66,7 @@ mount -t tmpfs -o size=50M tmpfs /var/lib/machines
 for bus in "${BUS_LIST[@]}"; do
     echo "Bus: $bus (system)"
     systemd-run --pipe --wait \
-                -- dfuzzer -v -b "$PAYLOAD_MAX" -n "$bus"
+                -- dfuzzer -b "$PAYLOAD_MAX" -n "$bus"
 
     # Let's reload the systemd daemon to test (de)serialization as well
     systemctl daemon-reload
@@ -83,7 +77,7 @@ umount /var/lib/machines
 for bus in "${SESSION_BUS_LIST[@]}"; do
     echo "Bus: $bus (session)"
     systemd-run --machine 'testuser@.host' --user --pipe --wait \
-                -- dfuzzer -v -b "$PAYLOAD_MAX" -n "$bus"
+                -- dfuzzer -b "$PAYLOAD_MAX" -n "$bus"
 
     # Let's reload the systemd user daemon to test (de)serialization as well
     systemctl --machine 'testuser@.host' --user daemon-reload