so I had an issue that I can use my Mac but if I tried to get into the recovery mode using the cmnd+r or option+cmn+r it would ask for a password with a lock on a black screen . I searched a lot on internet and couldn't find any answer . Finally found out that my dumbass put up a firmware password using the terminal so if you did the same and can't remember it just open the terminal and type the command sudo firmwarepasswd -check :-this command will let you check if there is a password it will ask for your Mac's login password type it to remove the firmware password sudo firmwarepasswd -delete. :-this command will delete the password type your Macs login password