Actually, as far as I know you can't degrade patches, once it's installed it's installed. The only other option you have is to remove the entire game, reinstall it, and not get ANY of the patches at all. But as soon as you permit patching it'll download all the patches available, including the one you mentioned, you can't control which specific patches will be installed.
<The only other option you have is to remove the entire game, reinstall it,>
and while doing so does anything happen to my saved games ? ..do they get erased too ? or if I reload the saved data on a downgraded game install, does the game load up ?
I don't know, you should try and see.
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Also there is another workaround, but it's difficult to make it happen as:
You must find another user that plays Fallout 4 on patch 1.2 (so online should be disabled) to run the game on that 1.2 patch.
Then if you have the same CUSA Product ID with him, you could ask him to start a new game with his 1.2 patched fallout 4 version.
If you load that particular file into your PS4, then it should work! (But remember to play offline, as the game will ask you to update before you play)
Thanks to all you Guyz
the path looks much streamlined than I previously thought. (for the records it takes up like 25 min . to finish this operation..but once done I was there again)
Thumbs up to all (y)