diff --git a/tf-psa-crypto/tests/suites/test_suite_psa_crypto_not_supported.function b/tf-psa-crypto/tests/suites/test_suite_psa_crypto_not_supported.function
index e5e66f482e..f37a1970aa 100644
--- a/tf-psa-crypto/tests/suites/test_suite_psa_crypto_not_supported.function
+++ b/tf-psa-crypto/tests/suites/test_suite_psa_crypto_not_supported.function
@@ -20,10 +20,28 @@ void import_not_supported(int key_type, data_t *key_material)
 
     PSA_ASSERT(psa_crypto_init());
     psa_set_key_type(&attributes, key_type);
-    TEST_EQUAL(psa_import_key(&attributes,
-                              key_material->x, key_material->len,
-                              &key_id),
-               PSA_ERROR_NOT_SUPPORTED);
+    psa_status_t actual_status =
+        psa_import_key(&attributes, key_material->x, key_material->len, &key_id);
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY)
+    if (actual_status == PSA_ERROR_INVALID_ARGUMENT) {
+        /* Edge case: when importing an ECC public key with an unspecified
+         * bit-size (as we do here), psa_import_key() infers the bit-size from
+         * the input. If the key type specifies an unknown curve, the validation
+         * might reject the data as invalid before it checks that the curve is
+         * supported. If so, that's ok. In practice, at the time of writing,
+         * this happens with Ed25519, for which a valid but unsupported
+         * 32-byte input causes psa_import_key() to fail because it
+         * assumes a Weierstrass curve which must have an odd-length
+         * encoding.
+         *
+         * In other cases, we do not expect an INVALID_ARGUMENT error here. */
+        TEST_ASSERT(PSA_KEY_TYPE_IS_ECC(key_type));
+    } else
+#endif /* defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY) */
+    {
+        TEST_EQUAL(actual_status, PSA_ERROR_NOT_SUPPORTED);
+    }
     TEST_ASSERT(mbedtls_svc_key_id_equal(key_id, MBEDTLS_SVC_KEY_ID_INIT));
 
 exit: