How to lock bootloader with stock os in moto e2? I have asked my to install custom rom. He unloacked the bootloader and installed custom rom.
After installed, my speakers and calling features are not worked.

I thought the problem is with custom rom. So I have thought to install the stock os again.

But I don't know how to install.
Can anyone please help me how to install the stock os and lock the bootloader again?
Just reinstalling the stock rom will not give you a locked bootloader. You will need to factory restart the phone by either going into the settings on the phone, or connecting it to a computer and using a utility there to factory reset.