You are welcome to read my ramblings as a random stranger, with a similar problem, but lacking the salt part.
I have described what I have done so that you can get an idea, should you wish to try. This was gleaned from information from Leo and reading a lot.
I have also (though it sounds like it’s too late to be of help) just created a post about stripping the core module, since I also found the iFixit teardown rather lacking. Stripping down the Core Module
When you say the FP2 doesn’t work, what DOES happen when you try?