Hardware back button in android not working

I updated the ionic version to 1.2.1 but still my $ionicPlaitform methods like registerBackButtonAction doesn’t work and also other methods.
I made my states static as well as dynamic still not working.
Please help me, as I raised this issue last year but still I got no response.
Non of the methods get called in run method. I tried all the blog solutions and stackoverflow answers couldn’t find any of them working.

thanks for your help in advance.