Is Your Mac Slow to Boot Up?
Always set the startup drive to speed boot time
Does your Mac take a long time to boot up?
Verify that you have selected a startup drive.
Otherwise, the Mac spends a lot of time looking around for which drive to boot from, even if there is only one. This definitely occurs after upgrading your boot drive.
Open System Preferences, then choose Startup Disk to set the desired drive as the startup drive.
