question for garmin firmware experts,

since support and updates for epix is ceased, and for some other watches garmin fixed issues with bluetooth connectivity, is it possible to modify epix firmware with updated bluetooth code from some other watch, like fenix 3, they should be most similar.
Epix uses version 3.20 and I believe fenix 5x has 3.30, don't know about fenix 3. I have Samsung J3, and epix can't communicate with it, that is why i'm asking.