The first thing I would try is resetting your NVRAM.
Resetting the NVRAM
Older Macs had what's called Parameter RAM (PRAM), newer Macs use Non-Volatile Random-Access Memory (NVRAM). Here’s how to reset the NVRAM on your model:
- Shut down your machine. Yes, a full shut down, not just logging out.
- Press the power button and then press the commandoptionpr keys. You have to make sure you press these keys before the gray screen appears or it won’t work.
- Hold those keys down until your Mac reboots again and you here the startup chime.
- Let go of the keys and let your Mac reboot normally.
Note: When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).