How to reset iMac lock passcode
My iMac is locked in firm lock and I misplaced my passcode. How can I get this fixed?
Please help.
[Re-Titled by Moderator]
Earlier Mac models
Go to > Set a firmware password on your Mac - Apple Support and read down to the last paragraph.
If you forgot your firmware password
If you can't remember your firmware password, schedule an in-person service appointment with an Apple Store or Apple Authorized Service Provider. Bring your Mac to the appointment, and bring your original receipt or invoice as proof of purchase.