Hi @Casey. Thanks for your thoughts on this problem.
Indeed, as I tried to make clear above, I cannot really exclude I did break the antenna contacts myself. One I certainly did.
No, I did not track this down because I heard something rattling inside the phone. I had previously opened the Pro1X's main body several times in the context of the battery depletion bug I had experienced, and because of the right-speaker-noise-at-full-charge issue. At that time, I did not pay much attention to the state of the contact springs (I did not even know what their purpose was). Though I do not rem