Isn't it time to think about starting anew with current technology rather than upgrading old equipment? I read lots of talk about improving ELTs, extending CVR time and other shortcommings.
With todays technology, all the flight information, airframe performance, position, speed, CVR, etc, could simply be uploaded in (almost) real-time via satellite then to ground stations/ATC. Such an change could easily be piggy-backed onto the existing recorders & flight systems and not really require much more than (another) computer and a satellite 'phone. In deed, as many aircraft now have WiFi internet access, all the data could be carried over that link.
There would never arise where the condition & position of any aircraft was not known or traceable to a few miles anywhere in the planet.