Up until this moment there was no solution - I had done the same crap and wound up with the same lockout issue - however I solved it thanks to some serious reading and experimenting - the solution leads through booting into shellx64.efi and running a dmpstore -b command - this will list all contents stored in the nvram - go through the list and look for variables ffm-computer-name, ffm-authentication-token-FFM, system-recovery-lock and other apple related variables and delete them with the command dmpstore -d variable name (e.g. variable = ffm-computer-name). Once you have cleaned it up exit efi shell by typing reset and boot into clover and osx installer - the 6 digit pin will be gone - and once u fix it don't mess with it again - took me 3 days to figure this out
P.S. Don't delete anything you are not sure about or you could wind up wrecking your entire UEFI system ... I haven't tried and I wouldn't - if in doubt - ask here.
