Regirock & Registeel/Regice

You will have to go through Clay Road to get here.. You will have to go through 4~5 mining carts before reaching here.. You will probably then see this empty room with a gigantic door. You can enter, but there isn't anything behind the door.. Inside, there's tips for you to unlock Regirock's room but you will have to visit this place in the day and night.. Assuming that you are using this blog as guide, I believed we are going for shortcut right? Once you are satisfied checking everything, even though there's nothing, get out from the room and stand at the middle of the circle like this picture.

Now move down 6 steps and move to the right 9 steps.. Face down (NOT MOVE) and click A.. You will notice a hidden switch.. Hit it and "something" will happen.. No worries if you got engaged into a wild poke battle, just continue what you did.. Cause this switch doesn't need you to follow exactly the step.. It's "fixed" location, means you can randomly hit A there without going through the sequence.. Though you will still have to face downward to hit the switch..

Now, go back to the room.. Regirock will be there waiting for you at Lvl 65.. Once you have caught it, there's an animation show that you have unlocked the next door.. Don't leave the cave or Escape Rope.. Cause we are going to catch these two Legends consecutively! Get out from the Regirock's room and save your game.. Turn off your DS and give it a break.. Switch on your Ds, and play the game like usual.. But don't hit "Continue" nor "New Game".. Go to Unova Link (イッシュリンク), then Key System (キーシステム), then the second option.. Now choose Mystery Door (ふしぎなとびら).. Then choose whichever one you unlocked earlier..

Then load your game like normal.. Enter the door again.. Now you will meet Registeel./Regice.. If you have another key unlocked somehow.. Then just repeat the process after you caught Regirock..