Hi,
installboot/usr/platform/'uname -i'/lib/fs/ufs/bootblk/dev/rdsk/c0t0d0s0
Here the above syntax what you have quoted is to install the corrupted bootblk, when your sparc machine fails to boot and still stands on Single user mode and from where you are not able to access dt logins.
so here is the description for the syntax
installboot - command to install the Primay Super bootblock or can call it as bootstrap program.
/usr/platform/'uname -i'/lib/fs/ufs/bootblk/ - in this loaction you can find the other secondary bootblk from where your sparc can boot.
usr - Library file
platform - keeps kernel independent modules to load
uname -i - Gives information of type of Installation you have done and Hardware platform for eg SUNW ,Sun Fire v490
lib - Is again a library file which keep binary files for the system
fs - Again a filesystem to which you are refereing to
ufs - is your Current Filesystem
bootblk - contains the bootblk program which you need to install using above command.
/dev/rdsk/c0t0d0s0 - is the location to install bootstrap program.
Still if you have doubts,. you can mail me
baraghan@vsnl.net
Regards