How to update

[aamaanaa]

if i have placed all the files from ffprofile into my firefox as a first time, then how do i update it? do i simply overwrite it with the new one ?

[allo-]

There is no good way to update. The generator builds an initial profile, but after using Firefox for some time you will have a lot of additional settings changed and just overwriting will reset them to defaults.

Currently the best way is probably to look at the last page in the preview section (or in the downloaded prefs.js) for options that are not set in your profile and add them to prefs.js when Firefox is not running or change them in about:config while Firefox is running.

A good solution would be to be able to merge settings, e.g., by removing the settings from an existing prefs.js file while keeping unrelated ones and then adding the new ones. Another option would be to allow users to select for each setting if they want to keep their version or use the generated value.
pseudo code:

for key in old_settings:
    if key in generated_settings:
        old_settings[key] = generated_settings[key]
return old_settings

In the best case it would be implemented in JavaScript, so the user's existing config is never sent to the server.

The relevant bug for adding this as feature is #25.