On the boot screen, I cannot select any other option by hitting "volume down" button (default selection is 1st in the list). Also, once the phone starts, the "volume down" button doesn't work. Therefore, I am thinking my "volume up" button is stuck. Which explains why the phone doesn't start in normal mode and gives me the boot screen (On/off switch with volume-up button).
To my surprise, once my phone starts I noticed following behavior.
(1) Pressed volume up button. On screen volume slider shows up and volume goes to max.
(2) I decreased the volume via "on screen" slider (not through volume down button).
(3) If volume up button was "stuck," as I thought, as soon as I let go the slider on the screen, volume should start increasing again. But it doesn't. Therefore, I am guessing, it might not be a button hardware issue.
Note: I tried the aforementioned three steps with my wife's Nexus 5 and on Nexus 7 by continuously holding down the volume up button. In step-3, as I expect, volume does start going up, as soon as I release the slider on screen.
Any help is appreciated. Thank you very much.