OK> .version OK> boot OK> boot cdrom press [stop]+[A] (Sun keyboard) to drop into OpenBoot
Using Debian sid netinst cd these days poses no problem on ULtra 10 machines. The Xserver is immediatly available after the first self-sustained boot.
SPARC replacement for lilo. The config is /boot/silo.conf. To force overwriting of first stage bootblock (see man page):
silo -f
PS: crash course Debian package manager: DebPackager