How to create an NVram alias for a hard drive or cd-rom - This example creates an alias to slice zero on SCSI target 2:

1. Drop to the open boot prom
2. List the controllers - Pick the one you need:

ok}  show-disks
     a) /pci@1f,4000/scsi@3/disk
     b) /pci@1f,4000/ebus@1/fdthree@14,3023f0
     q) NO SELECTION 
     
     Enter Selection, q to quit: a
        /pci@1f,4000/scsi@3/disk has been selected.
	Type ^Y ( Control-Y ) to insert it in the command line. 
	e.g. ok nvalias mydev ^Y 
	  for creating devalias mydev for 
	  /pci@1f,4000/scsi@3/disk

3. Use CONTROL-Y to insert the device path in the command below:

ok}  nvalias mydisk /pci@1f,4000/scsi@3/disk@2,0

4. Try to boot from your new device:

ok}  boot mydisk