Brightness slider, and volume control bus. 5.1

[AC Question]

I just updated my Nexus 4 to Android 5.1 a couple days ago. At first I was having an issue because my phone wouldn't turn on, and when it did it says in a red box "DOWNLOAD MODE". It was like that for a few hours and then started up and didn't recognise my SIM card. After several hours of it going between those 2 things it finally started working.
I was also having done issues with the " No interruptions for X amount of time not working.
Last thing is the brightness slider and sorry brightness mode aren't working. My phone is stuck having a very dark screen.
Any suggestions?

 

[B. Diddy]

Welcome to Android Central! Was it an OTA update, or did you manually install? It might be worth reflashing the factory image: How to manually update your Nexus | Android Central. Find the proper firmware here: https://developers.google.com/android/nexus/images