Mamba monster will not update settings

[LightningTC]

I have a mamba monster v2 that has never been used. I downloaded the firmware 1.20 and I updated it but it says it didnt get a response from the
controller. After unplug and plug it in again then it reads settings from the esc and says its now version 1.20 but If I change a setting and click update it will say no response from controller. Is it dead?