I am sorry that wasn't the information that you were looking for but perhaps this other info will shed some light on how to unlock yours.
How do I unlock my Mac computer?
To get started, you will need to restart your computer. Press the Command and R keys at the same time when the grey screen appears and hold them until you see the Apple logo. A small loading bar will appear under the logo. Sit tight as your system boots into Recovery Mode.
https://macprocleaner.com/unlock-recovery-hd-on-os-x-lion/
My startup disc starts, then stops. For some reason there is a lock symbol on my startup disc,so I cant get into the settings.
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