You are right Dafni. An software update should not affect the Mamba firmware. Usually when there is a major software revision the module firmware will come along with it and you will be prompted to install the firmware when installing the software. Not the case here. My first thought was that in the process of updating the software revision, the default settings are somehow changed but thinking about it more that shouldn't happen since the MM settings are retrieved fron the ESC when it is connected to the computer.
As I metnioned earlier I think the problem lies with the voltage or amperage coming from the fully charged pack. I'll play around with that some more and see what I can determine.
make sure you have the red wire pulled on the ESC going to Rx. It will run perfect at 19.2v with it installed, but at 21v it cuts out. It will run for a sec and shut off. Even if you pulled it, make sure it didnt slip back into the plug.