diff --git a/tests/psa-client-server/psasim/src/psa_sim_serialise.c b/tests/psa-client-server/psasim/src/psa_sim_serialise.c
index 703e4308f1..aaf47db0a3 100644
--- a/tests/psa-client-server/psasim/src/psa_sim_serialise.c
+++ b/tests/psa-client-server/psasim/src/psa_sim_serialise.c
@@ -110,8 +110,7 @@ static ssize_t allocate_aead_operation_slot(void)
 {
     psasim_client_handle_t handle = next_aead_operation_handle++;
     if (next_aead_operation_handle == 0) {      /* wrapped around */
-        fprintf(stderr, "MAX HASH HANDLES REACHED\n");
-        exit(1);
+        FATAL("Aead operation handle wrapped");
     }
 
     for (ssize_t i = 0; i < MAX_LIVE_HANDLES_PER_CLASS; i++) {
@@ -121,6 +120,8 @@ static ssize_t allocate_aead_operation_slot(void)
         }
     }
 
+    ERROR("All slots are currently used. Unable to allocate a new one.");
+
     return -1;  /* all in use */
 }
 
@@ -133,7 +134,9 @@ static ssize_t find_aead_slot_by_handle(psasim_client_handle_t handle)
         }
     }
 
-    return -1;  /* all in use */
+    ERROR("Unable to find slot by handle %u", handle);
+
+    return -1;  /* not found */
 }
 
 size_t psasim_serialise_begin_needs(void)
@@ -710,9 +713,3 @@ int psasim_deserialise_mbedtls_svc_key_id_t(uint8_t **pos,
 
     return 1;
 }
-
-void psa_sim_serialize_reset(void)
-{
-    memset(hash_operation_handles, 0, sizeof(hash_operation_handles));
-    memset(hash_operations, 0, sizeof(hash_operations));
-}
diff --git a/tests/psa-client-server/psasim/src/psa_sim_serialise.pl b/tests/psa-client-server/psasim/src/psa_sim_serialise.pl
index e09bb818a5..c795fd4dc9 100755
--- a/tests/psa-client-server/psasim/src/psa_sim_serialise.pl
+++ b/tests/psa-client-server/psasim/src/psa_sim_serialise.pl
@@ -724,6 +724,7 @@ sub c_header
  */
 
 #include "psa_sim_serialise.h"
+#include "util.h"
 #include <stdlib.h>
 #include <string.h>
 
@@ -788,6 +789,8 @@ sub define_operation_type_data_and_functions
 {
     my ($type) = @_;    # e.g. 'hash' rather than 'psa_hash_operation_t'
 
+    my $utype = ucfirst($type);
+
     return <<EOF;
 
 static psa_${type}_operation_t ${type}_operations[MAX_LIVE_HANDLES_PER_CLASS];
@@ -799,8 +802,7 @@ static ssize_t allocate_${type}_operation_slot(void)
 {
     psasim_client_handle_t handle = next_${type}_operation_handle++;
     if (next_${type}_operation_handle == 0) {      /* wrapped around */
-        fprintf(stderr, "MAX HASH HANDLES REACHED\\n");
-        exit(1);
+        FATAL("$utype operation handle wrapped");
     }
 
     for (ssize_t i = 0; i < MAX_LIVE_HANDLES_PER_CLASS; i++) {
@@ -810,6 +812,8 @@ static ssize_t allocate_${type}_operation_slot(void)
         }
     }
 
+    ERROR("All slots are currently used. Unable to allocate a new one.");
+
     return -1;  /* all in use */
 }
 
@@ -822,7 +826,9 @@ static ssize_t find_${type}_slot_by_handle(psasim_client_handle_t handle)
         }
     }
 
-    return -1;  /* all in use */
+    ERROR("Unable to find slot by handle %u", handle);
+
+    return -1;  /* not found */
 }
 EOF
 }