>        ... The only problem is that the machine
> does not want to boot from the disk. The disk
> is 1G, a few years newer than the machine.
> ....
> 
> Any ideas how to make it boot from the disk would be
> appreciated. Thank you in advance.

I'm afraid the news is not good here.  The rev C1 bootrom code was
apparently written under the assumption that any reasonable disk
would respond to SCSI selection pretty quickly, so the selection
phase timeout was set to something like 1 ms.  For reasons I don't
pretend to understand, a number of more modern disks often exceed
this, resulting in the bootrom not detecting them.  The timeout was
increased in the bootrom code for the 380 and 4xx machines but I
don't know of any newer official version that can be used in a 340.

-Steve