I pulled the sca drives and tried some external drives.  Same thing.

In the install script, where it calls the addtional files from 1) cdrom:

CD-ROM device to use [/dev/cd0a]:
esp0: unexpected disconnect; sending REQUEST SENSE
cd0(esp0:0:6:0): esp0: timed out [ecb 0xf03be000 (flags 0x5, dleft 20, stat 
0)],
 <state 5, nexus 0xf03be000, phase(l 1, c 1, p 1), resid 20, msg(q 20, o 80) 
DMA
 active>
cd0(esp0:0:6:0):sync negotiation disabled
cd0(esp0:0:6:0): esp0: timed out [ecb 0xf03be000 (flags 0x45, dleft 20, stat 
0)],
 <state 5, nexus 0xf03be000, phase(l 1, c 1, p 1) resid 20 msg(q 20, o 80) DMA
 active> AGAIN
sd0: async, 8-bit transfers
cd0: async, 8-bit transfers
esp0: invalid state: 6
esp0: invalid state: 6
esp0: invalid state: 6
....
10 times repeating
esp0: invalid state: 6
mount_cd9660L /dev/cd0a on /cdrom: Input/output error
This procedure supports one of the following media:

1) cdrom

etc, etc, etc, repeating each time you try to call up the cdrom files.

The cdrom reads fine by mounting on a machine.  The cdrom works
fine on 1.5.2, etc.  The hard drives work fine in 1.5.2 or on other machines.
The drives are sun Quantum 1g or sun 4.2g or Micropolis 9 g, etc.

My workaround was just to floppy boot and ftp install 1.6T and forget 1.6 or
1.6.1.  I had wanted to just be able to cdboot and install some generic
machines, but it just is not working out that way....

I just tried someting odd.... boot from cd, call up secondary files from 
FLOPPY,
then it continues up fine!!!!!!!!!!    Now, explain that one.....(:+}}...

Bob Keys