Unless you have a developer board (e.g., Radxa, BeagleBone) or a well-known chipset with community support, do not attempt a manual update . The Android 4.4 to 5.0 jump changed the runtime from Dalvik to ART, which requires different low-level drivers that old hardware almost never receives.

If you decide to proceed, always search for [Your Device Model] Lollipop firmware first – and never trust “universal Android 5.0 upgrade tools” from unknown websites (they are malware).