Um, I actually couldn't find second ending at first and saw your comment and did it, Then, i wondered if we could do not finishing maze in calder's route with no romantic interest with calder so in the end, that was the seventh ending. Just saying since many couldnt get seventh ending.
Well, it's always a pleasure as a fellow gamer to help each other's problem regarding the vn ^^
As for the 7th ending, thanks for the guide! But, it seems there is a glitch for some versions, which seems to be the center of the problem (inability to unlock the ending) , and the developers had regarded it well here