I bought xiaomi redmi 3 pro[32GB/3GB] lately and i've update my miui to miui v.8. The problem is my 4g lte was missing. So i want to downgrade my miui. But if i want to downgrade my phone must unlocked... but i worry my phone's warranty  will missed. So i want to ask about that or maybe there's another way to solve the missing of  4G LTE. Please give me the answer  as soon as possible. Thanks