From your recent photographs of the old hallway 2 switch it looks like blue = Common, red=L1 and yellow = L2. I cannot quite make out the terminal markings.
Back at the new switch:
Put the blue into the Left Hand L1 - Right Hand L1 stays empty.
Put the red into the Left Hand L2 (both reds should now be in here)
Put the yellow into the Right Hand L2 (yellow & black should be here)
If that doesn't work then either the wiring is not as it should be or the switch is broken - you might try it with a new one gang two way switch.
Back at the new switch:
Put the blue into the Left Hand L1 - Right Hand L1 stays empty.
Put the red into the Left Hand L2 (both reds should now be in here)
Put the yellow into the Right Hand L2 (yellow & black should be here)
If that doesn't work then either the wiring is not as it should be or the switch is broken - you might try it with a new one gang two way switch.