I've read on a couple of forms where people have had the issue of their phone randomly rebooting and starting up to a lock screen that reads (something like):
Secure startup 1/25 attempts
If you use a pattern code to lock your phone, the pin number will be the digits that you're pattern lock follows.
I don't know how else to word it.
Say your pattern followed the corners to 7391, your secure startup pin would be 7536951 So if you use a very complex pattern, it will just be every digit used that the pattern follows.
The attached visual reference would be 1598753
