diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 62828bd..b8abfd0 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3575,13 +3575,14 @@
     size_t *signature_length)
 {
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
-    mbedtls_mpi r;
-    mbedtls_mpi s;
 
 #if (defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)) && \
     defined(MBEDTLS_ECP_RESTARTABLE)
 
+    mbedtls_mpi r;
+    mbedtls_mpi s;
+
     if (signature_size < 2 * operation->coordinate_bytes) {
         return PSA_ERROR_BUFFER_TOO_SMALL;
     }
@@ -3790,6 +3791,7 @@
     (void) signature;
     (void) signature_length;
     (void) status;
+    (void) coordinate_bytes;
 
     return PSA_ERROR_NOT_SUPPORTED;
 #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) ||