| I have seen channels on amp die, so it is still a possibility the amp is dying.
On the NAV bit, the firmware will get you the latest Operating system for the NAV. If you want video, you will need a converter that will allow video to be injected to the system. BMW makes one for about 1000 USD and there are a few others out there for the same price. There are no simple/cheap solutions to allow you to play DVD's via the NAV. | 
