If you do not have floppy drive and your PROM is less than version 2, you will need to do a network boot. This is fairly easy to do, but you will need a rarp entry on a server on your local network to tell the target SPARC what it's IP address is. This can be done on a linux system that has RARP built into it's kernel (or inserted as a module) with a command of this form:
rarp -s ip.address.of.sparc hw:address:of:sparc
You also need an ARP entry in most cases. An example:
Now you need to setup a TFTP server on your local network to serve the kernel to the target SPARC. This should be the same machine that is doing the 'rarp' from above. Under Red Hat Linux, this can be done by editing your /etc/inetd.conf file. You need an entry that looks similar to:arp -s ip.address.of.sparc hw:address:of:sparc
tftp dgram udp wait root /usr/sbin/tcpd in.tftpd /home/tftp
You can now copy the file /images/vmlinux to /home/tftp on your server. You now will need to create a symbolic link so that the PROM can get the proper file. This symbolic link is conditional based on the IP address and architecture of the target SPARC. You need to make the link be the hex value of your IP address ``dot'' the architecture. For example, I have flanders.redhat.com with IP address 199.183.24.232. It is a sun4m machine. So, I would enter the command:
cd /home/tftp ln -s vmlinux C7B718E8.SUN4M
At this point you should be able to go to the PROM on your SPARC and type:
boot net nfsroot=nfs.server.IP.address:/path/to/RH/image
and it should get it's rarp request from the TFTP server fulfilled and start loading the kernel via TFTP. The kernel should then boot and start the install.
After booting the installation disk you will be greeted by a welcome
screen with a single button; press 
to begin the installation.
Now, choose the medium you will be installing from; NFS, Hard Disk or FTP. Installing from hard disk will work if you have an existing partition that is ext2 only. Installation from UFS is not implemented yet.