So I got the drive mounted and quick formatted (thanks Thomas) and went to copy the contents of old drive to new. (The whole point here is that disk validation can't validate dh0:, so I am adding the new drive. I seem to be able to read from dh0: fine, tho - can't write.)
I issued:
copy dh0:#? dh1: all clone quiet
...and it copied only files at the root level of the source disk, no subdirectories or their contents. Am I missing something?
Thanks.
bp