diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 6630c59..898240e 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1400,41 +1400,36 @@
                     char *result)
 {
     mbedtls_mpi X;
-    mbedtls_mpi_uint *N = NULL;
-    mbedtls_mpi_uint *res = NULL;
-    size_t limbs_N;
-    size_t limbs_res;
+    mbedtls_mpi N;
+    mbedtls_mpi res;
 
-    mbedtls_mpi_mod_modulus m;
     mbedtls_mpi_init(&X);
-    mbedtls_mpi_mod_modulus_init(&m);
+    mbedtls_mpi_init(&N);
+    mbedtls_mpi_init(&res);
 
-    TEST_EQUAL(mbedtls_test_read_mpi(&X, input_X), 0);
-    TEST_EQUAL(mbedtls_test_read_mpi_core(&N,   &limbs_N,   input_N), 0);
-    TEST_EQUAL(mbedtls_test_read_mpi_core(&res, &limbs_res, result),  0);
+    TEST_EQUAL(mbedtls_test_read_mpi(&X,   input_X), 0);
+    TEST_EQUAL(mbedtls_test_read_mpi(&N,   input_N), 0);
+    TEST_EQUAL(mbedtls_test_read_mpi(&res, result),  0);
 
-    size_t limbs = limbs_N;
+    TEST_ASSERT(mbedtls_mpi_core_uint_le_mpi(0, X.p, X.n));
+    TEST_ASSERT(mbedtls_mpi_core_uint_le_mpi(0, N.p, N.n));
+    TEST_ASSERT(mbedtls_mpi_core_uint_le_mpi(0, res.p, res.n));
+
+    size_t limbs = N.n;
     size_t bytes = limbs * sizeof(mbedtls_mpi_uint);
 
-    TEST_EQUAL(X.s,  1);
     TEST_LE_U(X.n, 448 / biL);
-    TEST_EQUAL(limbs_res, limbs);
-
-    TEST_EQUAL(mbedtls_mpi_mod_modulus_setup(
-                   &m, N, limbs,
-                   MBEDTLS_MPI_MOD_REP_MONTGOMERY), 0);
+    TEST_EQUAL(res.n, limbs);
 
     TEST_EQUAL(mbedtls_ecp_mod_p224k1(&X), 0);
+    TEST_EQUAL(mbedtls_mpi_mod_mpi(&X, &X, &N), 0);
     TEST_LE_U(mbedtls_mpi_core_bitlen(X.p, X.n), 224);
-    mbedtls_mpi_mod_raw_fix_quasi_reduction(X.p, &m);
-    ASSERT_COMPARE(X.p, bytes, res, bytes);
+    ASSERT_COMPARE(X.p, bytes, res.p, bytes);
 
 exit:
     mbedtls_mpi_free(&X);
-    mbedtls_free(res);
-
-    mbedtls_mpi_mod_modulus_free(&m);
-    mbedtls_free(N);
+    mbedtls_mpi_free(&N);
+    mbedtls_mpi_free(&res);
 }
 /* END_CASE */