Historically, Huawei hosted firmware on consumer.huawei.com . Today, they have removed public access. For MAR-LX3BM, your best official bet is HiSuite.

The Huawei P30 Lite (MAR-LX3BM) is officially upgradable to Android 10 with EMUI 10.0, which can be installed via over-the-air (OTA) updates in settings or by using the DLOAD method with a MicroSD card. This update improves system stability, adds new EMUI features, and provides necessary security patches. For detailed instructions on updating your system, see HUAWEI Support .