It is normally init -s or -S...
Othewise, Its so long ago... I think there was something in the logging screen menu, I think you had an option button you clicked to choose... I remember having to go...
You can also try to make a recovery archive on a DAT or a external disk using mkrs and boot from that to reinstall, or try to attach the disk as secondary, boot from the old and attempt to make it...
I wonder if it is not a question of driver... or firmware that needs to be updated... I dont remember how it was done ( I turned off my 712 in 94 and my 715 in 96...) I did uprade one so it...