diff --git a/configs/config-ccm-psk-dtls1_2.h b/configs/config-ccm-psk-dtls1_2.h
index df9301d2e..6134abc2e 100644
--- a/configs/config-ccm-psk-dtls1_2.h
+++ b/configs/config-ccm-psk-dtls1_2.h
@@ -101,3 +101,8 @@
  * them during tests/scripts/test-ref-configs.pl */
 //#define MBEDTLS_USE_PSA_CRYPTO
 //#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/configs/config-ccm-psk-tls1_2.h b/configs/config-ccm-psk-tls1_2.h
index 6ee7c4043..ea1cac677 100644
--- a/configs/config-ccm-psk-tls1_2.h
+++ b/configs/config-ccm-psk-tls1_2.h
@@ -92,3 +92,8 @@
  * them during tests/scripts/test-ref-configs.pl */
 //#define MBEDTLS_USE_PSA_CRYPTO
 //#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/configs/config-suite-b.h b/configs/config-suite-b.h
index 95c40875f..68ccf10cf 100644
--- a/configs/config-suite-b.h
+++ b/configs/config-suite-b.h
@@ -115,3 +115,8 @@
  * them during tests/scripts/test-ref-configs.pl */
 //#define MBEDTLS_USE_PSA_CRYPTO
 //#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/tests/scripts/test-ref-configs.pl b/tests/scripts/test-ref-configs.pl
index dc398c162..16fd4ecce 100755
--- a/tests/scripts/test-ref-configs.pl
+++ b/tests/scripts/test-ref-configs.pl
@@ -34,6 +34,8 @@ my %configs = (
     },
     'config-ccm-psk-dtls1_2.h' => {
         'compat' => '-m dtls12 -f \'^TLS-PSK-WITH-AES-...-CCM-8\'',
+        'opt' => ' ',
+        'opt_needs_debug' => 1,
         'test_again_with_use_psa' => 1
     },
     'config-no-entropy.h' => {
@@ -41,6 +43,8 @@ my %configs = (
     'config-suite-b.h' => {
         'compat' => "-m tls12 -f 'ECDHE-ECDSA.*AES.*GCM' -p mbedTLS",
         'test_again_with_use_psa' => 1,
+        'opt' => ' ',
+        'opt_needs_debug' => 1,
     },
     'config-symmetric-only.h' => {
         'test_again_with_use_psa' => 0, # Uses PSA by default, no need to test it twice
@@ -132,6 +136,15 @@ sub perform_test {
     my $opt = $data->{'opt'};
     if( $opt )
     {
+        if( $data->{'opt_needs_debug'} )
+        {
+            print "\nrebuilding with debug traces for ssl-opt\n";
+            system( "make clean" );
+            system( "scripts/config.py set MBEDTLS_DEBUG_C" );
+            system( "scripts/config.py set MBEDTLS_ERROR_C" );
+            system( "CFLAGS='-Os -Werror -Wall -Wextra' make" ) and abort "Failed to build: $conf +debug\n";
+        }
+
         print "\nrunning ssl-opt.sh $opt\n";
         system( "tests/ssl-opt.sh $opt" )
             and abort "Failed ssl-opt.sh: $conf\n";