Are lock screen pattern and system start pattern the same?

I have recently bought a Nokia 5 and I am quite new to Android. I have entered screen lock/and or start lock and entered a pattern. Acutally, I don't know if I did that one or two times but then I was very new to Android. After some time, I have changed the lock screen pattern. Now I enter that pattern daily many times, but I didn't turn it off for, say, two weeks. Now, after the installation of an update, the phone restarted and asked for a pattern to start Android. The lock screen pattern did not work. Since I entered the pattern too many times wrongly, the phone erased all data and I was forced to reinstall everything. Now I have entered a pattern (for lock screen) once again, and upon restarting the phone, the same pattern unlocked the phone. So the question: **Are lock screen pattern and system start pattern always the same or can the be different?**