However after it has loaded into the main screen, my phone vibrates (sorta a haptic-feedback vibration).
I have no clue what is calling this vibration. Initially I thought it was caused by my phone being on silent and it's notifying me that the phone is on vibration mode but I turned up the volume and I'm still getting it.
I noticed it was vibrating at around the same time my wifi toggle is enabled through the quick settings in the notification drop down. However, again I troubleshooted by switching off my wifi, reboot phone but I still get the vibrate.
I used logcat to see whether I could find out whether an app is calling a vibration but I can't really make any sense from it. I notice around 20 seconds into boot up there's a vibrator service showing up.