I bought an unlock code, but when I insert another sim it does not ask me for an unlock code. It just says unable to connect to network. I have read that one solution is to reinstall the stock firmware. I have downloaded the stock firmware but I am not able to flash it. RSDLite on my Windows 8.1 computer does not recognize my phone and when I try to do anything with fastboot it says variable not supported. I do have Linux partition on my computer if that helps, but I don't know what tool to use.
My main goal is to sim unlock the phone. If there is a way to do that without returning to stock, that is ok. Otherwise if someone could help me, I would appreciate it. If you need any more information I can give it to you.