Hello,
	there is a problem with wren VII's I remembered from when I was an
	Hotline engineer years ago...
	
SYNOPSIS: Can't boot a Wren VII drive on 4/75<PRE>

DETAIL DESCRIPTION:

Bug in Wren VII microcode. The bug shows up due to
		     the new Open Boot Proms on the 4/75.

		     This is only seen on Open Boot prom systems (4/75's at
		     this time). This disk works fine on 4/60s and 4/65s.

		     The Wren VII drive screws up when issued a &quot;spin 
up&quot;
		     command with the &quot;immediate&quot; bit set.  Sometime 
after
		     that command is issued a subsequent command will fail
		     (the particular command which fails is a &quot;read,&quot;
		     reporting an &quot;internal target error&quot; status).

		     The problem does not occur if the &quot;spin-up&quot; 
command
		     does not have the immediate bit set.  (The immediate
		     bit, when set, means that the device should start the
		     operation and then complete the SCSI transaction,
		     without making the CPU waiting for the operation to
		     complete.)



<h3>SOLUTION SUMMARY:</h3>

The workaround:

		     Add the following commands to the NVRAMRC file.  The
		     effect is to turn off the immediate bit on the spinup
		     command. 

			     ok nvedit
				0: true to fcode-debug?
				1: probe-all install-console banner
				2: cd /sd
				3: patch 0 1 sstart
				4: device-end
				5: ^C
			     ok nvstore
			     ok setenv use-nvramrc? true
			     use-nvramrc?=    true

		     Then power cycle.  Subsequent attempts to boot from
		     the Wren drive should be successful.