dynamic updation for bottom Toolbar image is not working on iPad but working in the simulator

I am trying to change bottom toolbar custom bottom image dynamically. It's working fine in simulator but not working in iPad.

I tried in following ways:

1. insert custom button and change the background image

2. using image view and adding as subview to button

I am running my code in iPad2 simulator version 8.1 and iPad2 version 8.2.