You may be able to download it from an outside source and flash it through stock recovery. But I don't know the recovery setup for your device, as each oem makes them slightly different.
You should post the specs of your phone. It's impossible to make a blind comment about this. I'll try to help you out once you reply with the information I need.
You should be able to update by downloading the FW somewhere else though if anything. Just food for thought.