Comment by trashb

> the NHTSA made them replace it

They forced them to replace it because it was recognized as a manufacturing/design defect. This is a very different scenario from "normal wear" replacement.

Additionally the Tesla model S is still in production with only a facelift. Therefore the parts that are produced are not unavailable (or not supplied).

I think you can't replace/upgrade the flash and modem yourself without the assistance of a Tesla dealer.