Re: TFTP boot w/ nfsroot
Just boot with tftpboot.img, that should get the installation going (if not,
you probably haven't gotten your tftp/rarp/bootp configuration correct).
After installation, replace the tftpboot.img with the linux-a.out kernel
which actually has nfsroot support nowadays. Both images is in the
disks-sparc directory of your favorite debian mirror.
You might have to give kernel paramaters to get the ip routing table
correct, I never got the ip configuration to work properly over BOOTP. I
hope this helps a little, if not, try to be more specific what you're after.