Modifying framework files



I am using a Teensy 3.2, and I am trying to test some modifications to its core files, that are part of the framework-arduinoteensy package.

I am using atom, and I am on Mac OS X El Capitan.

I am trying to do this by modifying the files in ~/.platformio/packages/framework-arduinoteensy/cores but when I compile, it does not appear that the changes are taking effect. I have even tested by making some drastic breaking changes, but my code will still compile just fine even after doing a clean build.

Am I missing a step, or some cached things that are preventing my changes from propagating? Is there a standardized way to create a development version of a package, to test with that I should follow to do this kind of thing?

Thank you!


Turn on verbose mode with pio run --version to see where are files located.