Do you want me to do anything with the information or just drop the subject ?
Maybe I misinterpreted what was in your (now deleted) post. It appeared to me at the time that you did not have a solution, you were just adding your problem on to the old one.
Now that you do have a solution I certainly don't think you should drop the subject since the information you got from DFROBOT will be of interest to others with the same problem.
Since this stuff is now a part of that old thread, and it is therefore no longer an old thread, it might be appropriate to put your solution here.
Another option would be to start a new thread with a link to that thread here. You could use a title of "SOLUTION to problem with serial lcd from YwRobot, LCM1602 IIC" or "Problem with serial lcd from YwRobot, LCM1602 IIC [SOLVED]".
In your post you should outline the symptoms and then give the solution that you found.
Don