diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index b232182..049cdb2 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -129,18 +129,12 @@
 }
 
 MBEDTLS_STATIC_TESTABLE
-int mbedtls_mpi_mod_raw_fix_quasi_reduction(mbedtls_mpi_uint *X,
-                                            const mbedtls_mpi_mod_modulus *N)
+void mbedtls_mpi_mod_raw_fix_quasi_reduction(mbedtls_mpi_uint *X,
+                                             const mbedtls_mpi_mod_modulus *N)
 {
-    if (N->limbs == 0) {
-        return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
-    }
-
     mbedtls_mpi_uint c = mbedtls_mpi_core_sub(X, X, N->p, N->limbs);
 
     (void) mbedtls_mpi_core_add_if(X, N->p, N->limbs, (unsigned) c);
-
-    return 0;
 }
 
 /* END MERGE SLOT 2 */
diff --git a/library/bignum_mod_raw_invasive.h b/library/bignum_mod_raw_invasive.h
index 7770c0a..3550eaf 100644
--- a/library/bignum_mod_raw_invasive.h
+++ b/library/bignum_mod_raw_invasive.h
@@ -43,8 +43,8 @@
  * \return      #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if \p N is invalid.
  */
 MBEDTLS_STATIC_TESTABLE
-int mbedtls_mpi_mod_raw_fix_quasi_reduction(mbedtls_mpi_uint *X,
-                                            const mbedtls_mpi_mod_modulus *N);
+void mbedtls_mpi_mod_raw_fix_quasi_reduction(mbedtls_mpi_uint *X,
+                                             const mbedtls_mpi_mod_modulus *N);
 
 #endif /* MBEDTLS_TEST_HOOKS */
 
diff --git a/tests/suites/test_suite_bignum_mod_raw.data b/tests/suites/test_suite_bignum_mod_raw.data
index 2b9b1ed..8cbd918 100644
--- a/tests/suites/test_suite_bignum_mod_raw.data
+++ b/tests/suites/test_suite_bignum_mod_raw.data
@@ -179,9 +179,6 @@
 mbedtls_mpi_mod_raw_cond_swap: copy half of the limbs
 mpi_mod_raw_cond_swap:"00000000FFFFFFFF55555555AAAAAAAA":"FEDCBA9876543210FEDCBA9876543210":8
 
-Bignum mod raw quasi-reduction: uninitialized modulus
-mpi_mod_raw_fix_quasi_reduction_neg:"11":"12":"1"
-
 # BEGIN MERGE SLOT 1
 
 # END MERGE SLOT 1
diff --git a/tests/suites/test_suite_bignum_mod_raw.function b/tests/suites/test_suite_bignum_mod_raw.function
index d59cdde..9e29130 100644
--- a/tests/suites/test_suite_bignum_mod_raw.function
+++ b/tests/suites/test_suite_bignum_mod_raw.function
@@ -369,7 +369,7 @@
                    &m, N, limbs,
                    MBEDTLS_MPI_MOD_REP_MONTGOMERY), 0);
 
-    TEST_EQUAL(mbedtls_mpi_mod_raw_fix_quasi_reduction(A, &m), 0);
+    mbedtls_mpi_mod_raw_fix_quasi_reduction(A, &m);
     ASSERT_COMPARE(A, bytes, res, bytes);
 
 exit:
@@ -381,55 +381,6 @@
 }
 /* END_CASE */
 
-/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
-void mpi_mod_raw_fix_quasi_reduction_neg(char *input_N,
-                                         char *input_A,
-                                         char *result)
-{
-    mbedtls_mpi_uint *A = NULL;
-    mbedtls_mpi_uint *N = NULL;
-    mbedtls_mpi_uint *res = NULL;
-    size_t limbs_A;
-    size_t limbs_N;
-    size_t limbs_res;
-
-    mbedtls_mpi_mod_modulus m;
-    mbedtls_mpi_mod_modulus_init(&m);
-
-    mbedtls_mpi_mod_modulus fake_m;
-    mbedtls_mpi_mod_modulus_init(&fake_m);
-
-    TEST_EQUAL(mbedtls_test_read_mpi_core(&A,   &limbs_A,   input_A), 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);
-
-    size_t limbs = limbs_N;
-    size_t bytes = limbs * sizeof(mbedtls_mpi_uint);
-
-    TEST_EQUAL(limbs_A,   limbs);
-    TEST_EQUAL(limbs_res, limbs);
-
-    TEST_EQUAL(mbedtls_mpi_mod_modulus_setup(
-                   &m, N, limbs,
-                   MBEDTLS_MPI_MOD_REP_MONTGOMERY), 0);
-
-    TEST_EQUAL(mbedtls_mpi_mod_raw_fix_quasi_reduction(A, &m), 0);
-    ASSERT_COMPARE(A, bytes, res, bytes);
-
-    /* Check when m is not initialized */
-    TEST_EQUAL(mbedtls_mpi_mod_raw_fix_quasi_reduction(A, &fake_m),
-               MBEDTLS_ERR_MPI_BAD_INPUT_DATA);
-
-exit:
-    mbedtls_free(A);
-    mbedtls_free(res);
-
-    mbedtls_mpi_mod_modulus_free(&fake_m);
-    mbedtls_mpi_mod_modulus_free(&m);
-    mbedtls_free(N);
-}
-/* END_CASE */
-
 /* BEGIN_CASE */
 void mpi_mod_raw_mul(char *input_A,
                      char *input_B,