Cannot boot from disk on ss20 running woody

[Christian Joensson]

I have woody installed on both an ss20 and an ss5. On the ss5 I boot 
from disk but that does not work onth ss20 @Illegal instruction@ 
something. I boot the ss20 from the rescue disk.

Any hints on how to get silo to boot from the ss20 disk?
TIA,

/ChJ