There have been lots of useful responses to this indicating that the OP didn't need to get into rebooting at all, but just to complete the picture...
Roger.Leonard@marconi.com writes:
my final recourse was to create boot floppies, bootfrom them, selecting "boot without rc" [...] very slow and tedious.
In ONTAP 6.x, you can get the menu that allows you to choose, e.g., booting without obeying /etc/rc, by using ctrl/C at the point in the booting process where it invites you to do that, all while booting from ordinary disk.
And of course, if you really do have to retreat to booting from floppies, you will have made a set in advance, and have tested booting from them as well. Otherwise you have shown a lamentable lack of pananoia... :)
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.