Can you help with firmware password

G_Willz wrote:

Firmware password required to boot my mac as I have changed the hard disk. I cannot ever remember setting this password.

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.

Set a firmware password on your Mac - Apple Support

https://osxdaily.com/2015/01/28/forgot-mac-firmware-password-what-now/

You do not say what exact Mac is this...

T2 Chip era (ie newer) Mac's the Storage is soldered to the board—here there a preferences for external boot up, unrecognized drives etc.

About Startup Security Utility - Apple Support

G_Willz wrote:

Macbook pro 2012

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.